diff options
Diffstat (limited to 'bin/ksh/sh.1tbl')
| -rw-r--r-- | bin/ksh/sh.1tbl | 908 |
1 files changed, 562 insertions, 346 deletions
diff --git a/bin/ksh/sh.1tbl b/bin/ksh/sh.1tbl index 7e7a8a76f60..25787a52e3e 100644 --- a/bin/ksh/sh.1tbl +++ b/bin/ksh/sh.1tbl @@ -1,4 +1,4 @@ -.\" $OpenBSD: sh.1tbl,v 1.16 1999/07/05 19:50:53 aaron Exp $ +.\" $OpenBSD: sh.1tbl,v 1.17 2000/03/17 18:15:16 aaron Exp $ .\" .\" Copyright (c) 1980, 1990, 1993 .\" The Regents of the University of California. All rights reserved. @@ -79,8 +79,10 @@ If neither the nor the .Fl s option is specified, the first non-option argument specifies the name -of a file the shell reads commands from. If there are no non-option -arguments, the shell reads commands from the standard input. The name of +of a file the shell reads commands from. +If there are no non-option +arguments, the shell reads commands from the standard input. +The name of the shell (i.e., the contents of $0) is determined as follows: if the .Fl c option is used and there is a non-option argument, it is used as the name; @@ -92,8 +94,8 @@ A shell is if the .Fl i option is used or if both standard input and standard error are attached -to a tty. An interactive shell has job control enabled (if available), -ignores the +to a tty. +An interactive shell has job control enabled (if available), ignores the .Dv SIGINT , .Dv SIGQUIT , and @@ -169,9 +171,11 @@ A privileged shell does not process .Pa $HOME/.profile nor the .Ev ENV -parameter (see below). Instead, the file +parameter (see below). +Instead, the file .Pa /etc/suid_profile -is processed. Clearing the privileged option causes the shell to set +is processed. +Clearing the privileged option causes the shell to set its effective user ID (group ID) to its real user ID (group ID). .Pp If the basename of the name the shell is called with (i.e., argv[0]) @@ -194,7 +198,8 @@ after any profiles are processed), its value is subjected to parameter, command, arithmetic, and tilde .Pq Sq \&~ substitution and the resulting file -(if any) is read and executed. If the +(if any) is read and executed. +If the .Ev ENV parameter is not set (and not .Dv NULL ) @@ -207,7 +212,8 @@ mentioned substitutions have been performed). .Pp The exit status of the shell is 127 if the command file specified on the command line could not be opened, or non-zero if a fatal syntax error -occurred during the execution of a script. In the absence of fatal errors, +occurred during the execution of a script. +In the absence of fatal errors, the exit status is that of the last command executed, or zero, if no command is executed. .Ss Command syntax @@ -225,8 +231,8 @@ and .Ql \&) .Pc . Aside from delimiting words, spaces and tabs are ignored, while newlines -usually delimit commands. The meta-characters are used in building the -following tokens: +usually delimit commands. +The meta-characters are used in building the following tokens: .Ql < , .Ql <& , .Ql << , @@ -260,7 +266,8 @@ or in groups using double .Pq Sq \&" or single .Pq Sq \&' -quotes. Note that the following characters are also treated specially by the +quotes. +Note that the following characters are also treated specially by the shell and must be quoted if they are to represent themselves: .Ql \e , .Ql \&" , @@ -331,8 +338,10 @@ input/output redirections (see .Sx Input/output redirections below), and command words; the only restriction is that parameter assignments come -before any command words. The command words, if any, define the command -that is to be executed and its arguments. The command may be a shell built-in +before any command words. +The command words, if any, define the command +that is to be executed and its arguments. +The command may be a shell built-in command, a function or an external command (i.e., a separate executable file that is located using the .Ev PATH @@ -346,7 +355,8 @@ this is related to the status returned by be executed, the exit status is 126); the exit status of other command constructs (built-in commands, functions, compound-commands, pipelines, lists, etc.) are all well-defined and are described where the construct is -described. The exit status of a command consisting only of parameter +described. +The exit status of a command consisting only of parameter assignments is that of the last command substitution performed during the parameter assignment or 0 is there were no command substitutions. .Pp @@ -355,8 +365,9 @@ Commands can be chained together using the token to form pipelines, in which the standard output of each command but the last is piped (see .Xr pipe 2 ) -to the standard input of the following command. The exit status of a pipeline -is that of its last command. A pipeline may be prefixed by the +to the standard input of the following command. +The exit status of a pipeline is that of its last command. +A pipeline may be prefixed by the .Ql ! reversed word which causes the exit status of the pipeline to be logically complemented: if the original status was 0 the complemented status will be 1; @@ -387,18 +398,20 @@ is non-zero. .Ql && and .Ql || -have equal precedence which is higher that that of +have equal precedence which is higher than that of .Ql & , .Ql |& and .Ql \&; , -which also have equal precedence. The +which also have equal precedence. +The .Ql & token causes the preceding command to be executed asynchronously; that is, the shell starts the command but does not wait for it to complete (the shell does keep track of the status of asynchronous commands, see .Sx Job control -below). When an asynchronous command is started when job control is disabled +below). +When an asynchronous command is started when job control is disabled (i.e., in most scripts), the command is started with signals .Dv SIGINT and @@ -418,7 +431,8 @@ or The exit status of a list is that of the last command executed, with the exception of asynchronous lists, for which the exit status is 0. .Pp -Compound commands are created using the following reserved words. These words +Compound commands are created using the following reserved words. +These words are only recognized if they are unquoted and if they are used as the first word of a command (i.e., they can't be preceded by parameter assignments or redirections): @@ -435,7 +449,8 @@ elif for time then } .Sy Note: Some shells (but not this one) execute control structure commands in a subshell when one or more of their file descriptors are redirected, so any -environment changes inside them may fail. To be portable, the +environment changes inside them may fail. +To be portable, the .Ic exec statement should be used instead to redirect file descriptors before the control structure. @@ -443,7 +458,8 @@ control structure. In the following compound command descriptions, command lists (denoted as .Em list ) that are followed by reserved words must end with a semicolon, a newline, or -a (syntactically correct) reserved word. For example, +a (syntactically correct) reserved word. +For example, .Pp .Bl -inset -indent -compact .It Ic { echo foo; echo bar; } @@ -462,12 +478,14 @@ is not. .It Ic \&( Ar list Ic \&) Execute .Ar list -in a subshell. There is no implicit way to pass environment changes from a +in a subshell. +There is no implicit way to pass environment changes from a subshell back to its parent. .It Ic \&{ Ar list Ic \&} Compound construct; .Ar list -is executed, but not in a subshell. Note that +is executed, but not in a subshell. +Note that .Ic \&{ and .Ic \&} @@ -487,19 +505,21 @@ against the specified .Ar pattern Ns s ; the .Ar list -associated with the first successfully matched pattern is executed. Patterns -used in +associated with the first successfully matched pattern is executed. +Patterns used in .Ic case statements are the same as those used for file name patterns except that the restrictions regarding .Ql \&. and .Ql / -are dropped. Note that any unquoted space before and after a pattern is -stripped; any space with a pattern must be quoted. Both the word and the +are dropped. +Note that any unquoted space before and after a pattern is +stripped; any space with a pattern must be quoted. +Both the word and the patterns are subject to parameter, command, and arithmetic substitution, as -well as tilde substitution. For historical reasons, open and close braces -may be used instead of +well as tilde substitution. +For historical reasons, open and close braces may be used instead of .Ic in and .Ic esac @@ -522,11 +542,12 @@ in the specified word list, the parameter .Ar name is set to the word and .Ar list -is executed. If +is executed. +If .Ic in is not used to specify a word list, the positional parameters ($1, $2, etc.) -are used instead. For historical reasons, open and close braces may be used -instead of +are used instead. +For historical reasons, open and close braces may be used instead of .Ic do and .Ic done @@ -555,8 +576,8 @@ is executed; otherwise, the .Ar list following the .Ic elif , -if any, is executed with similar consequences. If all the lists following -the +if any, is executed with similar consequences. +If all the lists following the .Ic if and .Ic elif Ns s @@ -564,7 +585,8 @@ fail (i.e., exit with non-zero status), the .Ar list following the .Ic else -is executed. The exit status of an +is executed. +The exit status of an .Ic if statement is that of non-conditional .Ar list @@ -584,10 +606,11 @@ is non-zero. .Xc A .Ic while -is a pre-checked loop. Its body is executed as often as the exit status of -the first +is a pre-checked loop. +Its body is executed as often as the exit status of the first .Ar list -is zero. The exit status of a +is zero. +The exit status of a .Ic while statement is the last exit status of the .Ar list @@ -599,7 +622,8 @@ Defines the function .Ar name (see .Sx Functions -below). Note that redirections specified after a function definition are +below). +Note that redirections specified after a function definition are performed whenever the function is executed, not when the function definition is executed. .It Ar name Ic () Ar command @@ -611,15 +635,18 @@ below). .El .Ss Quoting Quoting is used to prevent the shell from treating characters or words -specially. There are three methods of quoting. First, +specially. +There are three methods of quoting. +First, .Ql \e quotes the following character, unless it is at the end of a line, in which case both the .Ql \e -and the newline are stripped. Second, a single quote +and the newline are stripped. +Second, a single quote .Pq Sq ' -quotes everything up to the next single quote (this may span lines). Third, -a double quote +quotes everything up to the next single quote (this may span lines). +Third, a double quote .Pq Sq \&" quotes all characters, except .Ql $ , @@ -632,7 +659,8 @@ and .Ql ` inside double quotes have their usual meaning (i.e., parameter, command or arithmetic substitution) except no field splitting is carried out on the -results of double-quoted substitutions. If a +results of double-quoted substitutions. +If a .Ql \e inside a double-quoted string is followed by .Ql \e , @@ -655,13 +683,15 @@ below for a special rule regarding sequences of the form .Ss Aliases There are two types of aliases: normal command aliases and tracked aliases. Command aliases are normally used as a short hand for a long or often used -command. The shell expands command aliases (i.e., substitutes the alias name -for its value) when it reads the first word of a command. An expanded alias -is re-processed to check for more aliases. If a command alias ends in a -space or tab, the following word is also checked for alias expansion. The -alias expansion process stops when a word that is not an alias is found, when -a quoted word is found or when an alias word that is currently being expanded -is found. +command. +The shell expands command aliases (i.e., substitutes the alias name +for its value) when it reads the first word of a command. +An expanded alias is re-processed to check for more aliases. +If a command alias ends in a +space or tab, the following word is also checked for alias expansion. +The alias expansion process stops when a word that is not an alias is found, +when a quoted word is found or when an alias word that is currently being +expanded is found. .Pp The following command aliases are defined automatically by the shell: .Pp @@ -673,22 +703,26 @@ The following command aliases are defined automatically by the shell: .El .Pp Tracked aliases allow the shell to remember where it found a particular -command. The first time the shell does a path search for a command that is -marked as a tracked alias, it saves the full path of the command. The next +command. +The first time the shell does a path search for a command that is +marked as a tracked alias, it saves the full path of the command. +The next time the command is executed, the shell checks the saved path to see that it -is still valid, and if so, avoids repeating the path search. Tracked aliases -can be listed and created using +is still valid, and if so, avoids repeating the path search. +Tracked aliases can be listed and created using .Ic alias -t . Note that changing the .Ev PATH -parameter clears the saved paths for all tracked aliases. If the +parameter clears the saved paths for all tracked aliases. +If the .Ic trackall option is set (i.e., .Ic set Fl o Ic trackall or .Ic set Fl h ) , -the shell tracks all commands. This option is set automatically for -non-interactive shells. For interactive shells, only the following commands are +the shell tracks all commands. +This option is set automatically for non-interactive shells. +For interactive shells, only the following commands are automatically tracked: .Ic cat , cc , chmod , cp , .Ic date , ed , emacs , grep , @@ -699,14 +733,16 @@ and .Ic who . .Ss Substitution The first step the shell takes in executing a simple-command is to perform -substitutions on the words of the command. There are three kinds of -substitution: parameter, command, and arithmetic. Parameter substitutions, +substitutions on the words of the command. +There are three kinds of +substitution: parameter, command, and arithmetic. +Parameter substitutions, which are described in detail in the next section, take the form -.Ic $name +.Ic $ Ns Ar name or -.Ic ${...} ; +.Ic ${ Ns Ar ... Ns Ic \&} ; command substitutions take the form -.Ic $( Ns Ar command Ns Ic ) +.Ic $( Ns Ar command Ns Ic \&) or .Ic ` Ns Ar command Ns Ic ` ; and arithmetic substitutions take the form @@ -716,7 +752,8 @@ If a substitution appears outside of double quotes, the results of the substitution are generally subject to word or field splitting according to the current value of the .Ev IFS -parameter. The +parameter. +The .Ev IFS parameter specifies a list of characters which are used to break a string up into several words; any characters from the set space, tab, and newline that @@ -729,7 +766,8 @@ Sequences of one or more whitespace characters, in combination with zero or no .Pf non- Ev IFS whitespace -characters, delimit a field. As a special case, leading and trailing +characters, delimit a field. +As a special case, leading and trailing .Ev IFS whitespace is stripped (i.e., no leading or trailing empty field is created by it); leading or trailing @@ -756,7 +794,8 @@ string, no field splitting is done; if the parameter is unset, the default value of space, tab, and newline is used. .Pp Also, note that the field splitting applies only to the immediate result of -the substitution. Using the previous example, the substitution for $VAR:E +the substitution. +Using the previous example, the substitution for $VAR:E results in the fields: .Dq A , .Dq B , @@ -779,8 +818,9 @@ The results of substitution are, unless otherwise specified, also subject to brace expansion and file name expansion (see the relevant sections below). .Pp A command substitution is replaced by the output generated by the specified -command, which is run in a subshell. For -.Ic $( Ns Ar command Ns Ic ) +command, which is run in a subshell. +For +.Ic $( Ns Ar command Ns Ic \&) substitutions, normal quoting rules are used when .Ar command is parsed; however, for the @@ -794,8 +834,8 @@ or .Ql \e is stripped (a .Ql \e -followed by any other character is unchanged). As a special case in command -substitutions, a command of the form +followed by any other character is unchanged). +As a special case in command substitutions, a command of the form .Ic \&< Ar file is interpreted to mean substitute the contents of .Ar file @@ -808,17 +848,20 @@ but it is carried out more efficiently because no process is started). .Sy Note: .Ic $( Ns Ar command Ns Ic \&) expressions are currently parsed by finding the matching parenthesis, -regardless of quoting. This should be fixed soon. +regardless of quoting. +This should be fixed soon. .Pp Arithmetic substitutions are replaced by the value of the specified expression. For example, the command .Ic echo $((2+3*4)) -prints 14. See +prints 14. +See .Sx Arithmetic expressions for a description of an expression. .Ss Parameters Parameters are shell variables; they can be assigned values and their values -can be accessed using a parameter substitution. A parameter name is either one +can be accessed using a parameter substitution. +A parameter name is either one of the special single punctuation or digit character parameters described below, or a letter followed by zero or more letters or digits .Po @@ -831,10 +874,9 @@ or .Ic ${ Ns Ar name Ns Ic \&} , where .Ar name -is a parameter name. If substitution is performed on a parameter that is not -set, a -.Dv NULL -string is substituted unless the +is a parameter name. +If substitution is performed on a parameter that is not set, a +null string is substituted unless the .Ic nounset option .Po @@ -844,12 +886,12 @@ or .Pc is set, in which case an error occurs. .Pp -Parameters can be assigned valued in a number of ways. First, the shell -implicitly sets some parameters like +Parameters can be assigned valued in a number of ways. +First, the shell implicitly sets some parameters like .Ic # , PWD , etc.; this is the only way the special single character parameters are set. -Second, parameters are imported from the shell's environment at startup. Third, -parameters can be assigned values on the command line, for example, +Second, parameters are imported from the shell's environment at startup. +Third, parameters can be assigned values on the command line, for example, .Ic FOO=bar sets the parameter .Ev FOO @@ -858,25 +900,27 @@ to multiple parameter assignments can be given on a single command line and they can be followed by a simple-command, in which case the assignments are in effect only for the duration of the command (such assignments are also -exported, see below for implications of this). Note that both the parameter -name and the +exported, see below for implications of this). +Note that both the parameter name and the .Ql = -must be unquoted for the shell to recognize a parameter assignment. The fourth -way of setting a parameter is with the +must be unquoted for the shell to recognize a parameter assignment. +The fourth way of setting a parameter is with the .Ic export , .Ic readonly and .Ic typeset commands; see their descriptions in the .Sx Command execution -section. Fifth, +section. +Fifth, .Ic for loops set parameters as well as the .Ic getopts , .Ic read and .Ic set Fl A -commands. Lastly, parameters can be assigned values using assignment operators +commands. +Lastly, parameters can be assigned values using assignment operators inside arithmetic expressions (see .Sx Arithmetic expressions below) or using the @@ -894,8 +938,10 @@ the environment (see .Xr environ 5 ) of commands run by the shell as .Ar name Ns No = Ns Ar value -pairs. The order in which parameters appear in the environment of a command is -unspecified. When the shell starts up, it extracts parameters and their values +pairs. +The order in which parameters appear in the environment of a command is +unspecified. +When the shell starts up, it extracts parameters and their values from its environment and automatically sets the export attribute for those parameters. .Pp @@ -946,7 +992,8 @@ it is substituted; otherwise, is printed on standard error (preceded by .Ar name Ns No \&: ) and an error occurs (normally causing termination of a shell script, function -or .-script). If word is omitted the string +or .-script). +If word is omitted the string .Dq parameter null or not set is used instead. .El @@ -989,7 +1036,8 @@ If .Ar pattern matches the beginning of the value of parameter .Ar name , -the matched text is deleted from the result of substitution. A single +the matched text is deleted from the result of substitution. +A single .Ql # results in the shortest match, and two of them result in the longest match. @@ -1008,8 +1056,8 @@ The following special parameters are implicitly set by the shell and cannot be set directly using assignments: .Bl -tag -width "1 ... 9" .It Ev \&! -Process ID of the last background process started. If no background processes -have been started, the parameter is not set. +Process ID of the last background process started. +If no background processes have been started, the parameter is not set. .It Ev \&# The number of positional parameters (i.e., $1, $2, etc.). .It Ev \&$ @@ -1022,8 +1070,8 @@ The concatenation of the current single letter options (see .Ic set command below for list of options). .It Ev \&? -The exit status of the last non-asynchronous command executed. If the last -command was killed by a signal, +The exit status of the last non-asynchronous command executed. +If the last command was killed by a signal, .Ic \&$\&? is set to 128 plus the signal number. .It Ev 0 @@ -1037,17 +1085,20 @@ option and the .Ar command-name was supplied, or the .Ar file -argument, if it was supplied. If the +argument, if it was supplied. +If the .Ic posix option is not set, .Ic \&$0 is the name of the current function or script. .It Ev 1 ... Ev 9 The first nine positional parameters that were supplied to the shell, function -or .-script. Further positional parameters may be accessed using +or .-script. +Further positional parameters may be accessed using .Ic ${ Ns Ar number Ns Ic \&} . .It Ev \&* -All positional parameters (except parameter 0), i.e., $1, $2, $3... If used +All positional parameters (except parameter 0), i.e., $1, $2, $3... +If used outside of double quotes, parameters are separate words (which are subjected to word splitting); if used within double quotes, parameters are separated by the first character of the @@ -1060,8 +1111,8 @@ is Same as .Ic \&$\&* , unless it is used inside double quotes, in which case a separate word is -generated for each positional parameter. If there are no positional parameters, -no word is generated. +generated for each positional parameter. +If there are no positional parameters, no word is generated. .Ic \&$\&@ can be used to access arguments, verbatim, without losing .Dv NULL @@ -1073,39 +1124,45 @@ The following parameters are set and/or used by the shell: .It Ev CDPATH Search path for the .Ic cd -built-in command. Works the same way as +built-in command. +Works the same way as .Ev PATH for those directories not beginning with .Ql / in .Ic cd -commands. Note that if +commands. +Note that if .Ev CDPATH is set and does not contain .Dq \&. -or contains an empty path, the current directory is not searched. Also, the +or contains an empty path, the current directory is not searched. +Also, the .Ic cd built-in command will display the resulting directory when a match is found in any search path other than the empty path. .It Ev COLUMNS -Set to the number of columns on the terminal or window. Currently set to the +Set to the number of columns on the terminal or window. +Currently set to the .Dq cols value as reported by .Xr stty 1 -if that value is non-zero. This parameter is used by +if that value is non-zero. +This parameter is used by .Ic set Fl o and .Ic kill -l commands to format information columns. .It Ev ENV If this parameter is found to be set after any profile files are executed, the -expanded value is used as a shell startup file. It typically contains function -and alias definitions. +expanded value is used as a shell startup file. +It typically contains function and alias definitions. .It Ev ERRNO Integer value of the shell's .Va errno -variable. It indicates the reason the last system call failed. Not yet -implemented. +variable. +It indicates the reason the last system call failed. +Not yet implemented. .It Ev EXECSHELL If set, this parameter is assumed to contain the shell that is to be used to execute commands that @@ -1121,7 +1178,8 @@ command (see below). Like .Ev PATH , but used when an undefined function is executed to locate the file defining the -function. It is also searched when a command can't be found using +function. +It is also searched when a command can't be found using .Ev PATH . See .Sx Functions @@ -1138,7 +1196,8 @@ below). Internal field separator, used during substitution and by the .Ic read command, to split values into distinct arguments; normally set to space, tab -and newline. See +and newline. +See .Sx Substitution above for details. .Pp @@ -1151,9 +1210,11 @@ The version of shell and the date the version was created (read-only). The line number of the function or shell script that is currently being executed. .It Ev LINES -Set to the number of lines on the terminal or window. Not yet implemented. +Set to the number of lines on the terminal or window. +Not yet implemented. .It Ev OLDPWD -The previous working directory. Unset if +The previous working directory. +Unset if .Ic cd has not successfully changed directories since the shell started, or if the shell doesn't know where it is. @@ -1169,14 +1230,16 @@ Assigning 1 to this parameter causes to process arguments from the beginning the next time it is invoked. .It Ev PATH A colon separated list of directories that are searched when looking for -commands and .'d files. An empty string resulting from a leading or trailing +commands and .'d files. +An empty string resulting from a leading or trailing colon, or two adjacent colons, is treated as a .Dq \&. , the current directory. .It Ev POSIXLY_CORRECT If set, this parameter causes the .Ic posix -option to be enabled. See +option to be enabled. +See .Sx POSIX mode below. .It Ev PPID @@ -1195,11 +1258,13 @@ used when more input is needed to complete a command. .It Ev PS4 Used to prefix commands that are printed during execution tracing (see .Ic set Fl x -command below). The prompt is printed verbatim (i.e., no substitutions are -done). Default is +command below). +The prompt is printed verbatim (i.e., no substitutions are done). +Default is .Dq \&+\ \& . .It Ev PWD -The current working directory. May be unset or +The current working directory. +May be unset or .Dv NULL if the shell doesn't know where it is. .It Ev REPLY @@ -1207,7 +1272,8 @@ Default parameter for the .Ic read command if no names are given. .It Ev TMPDIR -The directory shell temporary files are created in. If this parameter is not +The directory shell temporary files are created in. +If this parameter is not set, or does not contain the absolute path of a writable directory, temporary files are created in .Pa /tmp . @@ -1218,7 +1284,8 @@ on words starting with an unquoted .Ql ~ . The characters following the tilde, up to the first .Ql / , -if any, are assumed to be a login name. If the login name is empty, +if any, are assumed to be a login name. +If the login name is empty, .Ql + or .Ql - , @@ -1227,9 +1294,11 @@ the value of the .Ev PWD , or .Ev OLDPWD -parameter is substituted, respectively. Otherwise, the password file is +parameter is substituted, respectively. +Otherwise, the password file is searched for the login name, and the tilde expression is substituted with the -user's home directory. If the login name is not found in the password file or +user's home directory. +If the login name is not found in the password file or if any quoting or parameter substitution occurs in the login name, no substitution is performed. .Pp @@ -1256,30 +1325,34 @@ or .Ql * characters or .Dq [..] -sequences. Once brace expansion has been performed, the shell replaces file +sequences. +Once brace expansion has been performed, the shell replaces file name patterns with the sorted named of all the files that match the pattern -(if no files match, the word is left unchanged). The pattern elements have the -following meaning: +(if no files match, the word is left unchanged). +The pattern elements have the following meaning: .Bl -tag -width Ds .It Ic \&? Matches any single character. .It Ic \&* Matches any sequence of characters. .It Ic \&[ Ns No .. Ns Ic \&] -Matches any of the characters inside the brackets. Ranges of characters can be +Matches any of the characters inside the brackets. +Ranges of characters can be specified by separating two characters by a .Ql - (e.g., .Dq [a0-9] matches the letter .Dq a -or any digit). In order to represent itself, a +or any digit). +In order to represent itself, a .Ql - must either be quoted or the first or last character in the character list. Similarly, a .Ql \&] must be quoted or the first character in the list if it is to represent itself -instead of the end of the list. Also, a +instead of the end of the list. +Also, a .Ql ! appearing at the start of the list has special meaning (see below), so to represent itself it must be quoted or appear later in the list. @@ -1332,7 +1405,8 @@ expression) are not yet implemented. .Ss Input/output redirection When a command is executed, its standard input, standard output, and standard error (file descriptors 0, 1, and 2, respectively) are normally inherited from -the shell. Three exceptions to this are commands in pipelines, for which +the shell. +Three exceptions to this are commands in pipelines, for which standard input and/or standard output are those set up by the pipeline, asynchronous commands created when job control is disabled, for which standard input is initially set to be from @@ -1346,8 +1420,8 @@ If .Ar file does not exist, it is created; if it does exist, is a regular file and the .Ic noclobber -option is set, an error occurs; otherwise, the file is truncated. Note that this -means the command +option is set, an error occurs; otherwise, the file is truncated. +Note that this means the command .Ic cmd < foo > foo will open .Ar foo @@ -1366,7 +1440,8 @@ Same as .Ic \&> , except if .Ar file -exists it is appended to instead of being truncated. Also, the file is opened +exists it is appended to instead of being truncated. +Also, the file is opened in append mode, so writes always go to the end of the file (see .Fn open 2 ) . .It Ic \&< Ar file @@ -1383,8 +1458,10 @@ After reading the command line containing this kind of redirection (called a the shell copies lines from the command source into a temporary file until a line matching .Ar marker -is read. When the command is executed, standard input is redirected from the -temporary file. If +is read. +When the command is executed, standard input is redirected from the +temporary file. +If .Ar marker contains no quoted characters, the contents of the temporary file are processed as if enclosed in double quotes each time the command is executed, so @@ -1396,7 +1473,7 @@ escapes for .Ql ` , .Ql \e , and -.Dq \enewline . +.Ql \enewline . If multiple here documents are used on the same command line, they are saved in order. .It Ic \&<\&<\&- Ar marker @@ -1422,16 +1499,19 @@ except the operation is done on standard output. .Pp In any of the above redirections, the file descriptor that is redirected (i.e., standard input or standard output) can be explicitly given by preceding the -redirection with a single digit. Parameter, command, and arithmetic +redirection with a single digit. +Parameter, command, and arithmetic substitutions, tilde substitutions, and (if the shell is interactive) file name generation are all performed on the .Ar file , .Ar marker and .Ar fd -arguments of redirections. Note, however, that the results of any file name +arguments of redirections. +Note, however, that the results of any file name generation are only used if a single file is matched; if multiple files match, -the word with the expanded file name generation characters is used. Note +the word with the expanded file name generation characters is used. +Note that in restricted shells, redirections which can create files cannot be used. .Pp For simple-commands, redirections may appear anywhere in the command; for @@ -1440,7 +1520,8 @@ compound-commands .Ic if statements, etc. .Pc , -any redirections must appear at the end. Redirections are processed after +any redirections must appear at the end. +Redirections are processed after pipelines are created and in the order they are given, so .Pp .Ic cat /foo/bar 2\&>&1 \&> /dev/null \&| cat -n @@ -1535,7 +1616,8 @@ Arithmetic (bit-wise) .Tn NOT . .It Ic \&+\&+ Increment; must be applied to a parameter (not a literal or other expression). -The parameter is incremented by 1. When used as a prefix operator, the result +The parameter is incremented by 1. +When used as a prefix operator, the result is the incremented value of the parameter; when used as a postfix operator, the result is the original value of the parameter. .It Ic \&-\&- @@ -1544,8 +1626,8 @@ Similar to except the parameter is decremented by 1. .It Ic \&, Separates two arithmetic expressions; the left-hand side is evaluated first, -then the right. The result is the value of the expression on the right-hand -side. +then the right. +The result is the value of the expression on the right-hand side. .It Ic = Assignment; variable on the left is set to the value on the right. .It Xo Ic \&*= /= \&+= \&-= \&<\&<= @@ -1565,13 +1647,13 @@ is the same as .It Ic \&|\&| Logical .Tn OR ; -the result is 1 if either argument is non-zero, 0 if not. The right -argument is evaluated only if the left argument is zero. +the result is 1 if either argument is non-zero, 0 if not. +The right argument is evaluated only if the left argument is zero. .It Ic \&&\&& Logical .Tn AND ; -the result is 1 if both arguments are non-zero, 0 if not. The -right argument is evaluated only if the left argument is non-zero. +the result is 1 if both arguments are non-zero, 0 if not. +The right argument is evaluated only if the left argument is non-zero. .It Ic \&| Arithmetic (bit-wise) .Tn OR . @@ -1590,7 +1672,8 @@ Not equal; the result is 0 if both arguments are equal, 1 if not. Less than; the result is 1 if the left argument is less than the right, 0 if not. .It Ic \&<= \&>= \&> -Less than or equal, greater than or equal, greater than. See +Less than or equal, greater than or equal, greater than. +See .Ic \&< . .It Ic \&<\&< \&>\&> Shift left (right); the result is the left argument with its bits shifted left @@ -1599,8 +1682,8 @@ Shift left (right); the result is the left argument with its bits shifted left Addition, subtraction, multiplication, and division. .It Ic % Remainder; the result is the remainder of the division of the left argument by -the right. The sign of the result is unspecified if either argument is -negative. +the right. +The sign of the result is unspecified if either argument is negative. .It Xo Ao Ar arg1 Ac Ic \ \&? .Ao Ar arg2 Ac Ic \ \&: Ao Ar arg3 Ac .Xc @@ -1616,12 +1699,15 @@ Functions are defined using either Korn shell .Ic function Ar name syntax or the Bourne/POSIX shell .Fn name -syntax (see below for the difference between the two forms). Functions are like +syntax (see below for the difference between the two forms). +Functions are like .Li .-scripts -in that they are executed in the current environment. However, unlike +in that they are executed in the current environment. +However, unlike .Li .-scripts , shell arguments (i.e., positional parameters $1, $2, etc.) are never visible -inside them. When the shell is determining the location of a command, functions +inside them. +When the shell is determining the location of a command, functions are searched after special built-in commands, before regular and non-regular built-ins, and before the .Ev PATH @@ -1640,7 +1726,8 @@ may be used to create undefined functions; when an undefined function is executed, the shell searches the path specified in the .Ev FPATH parameter for a file with the same name as the function, which, if found, is -read and executed. If after executing the file the named function is found to +read and executed. +If after executing the file the named function is found to be defined, the function is executed; otherwise, the normal command search is continued (i.e., the shell searches the regular built-in command table and .Ev PATH ) . @@ -1658,24 +1745,28 @@ which can be set with .Ic typeset \&-ft and .Ic typeset \&-fx , -respectively. When a traced function is executed, the shell's +respectively. +When a traced function is executed, the shell's .Ic xtrace option is turned on for the function's duration; otherwise, the .Ic xtrace -option is turned off. The +option is turned off. +The .Dq export -attribute of functions is currently not used. In the original Korn shell, +attribute of functions is currently not used. +In the original Korn shell, exported functions are visible to shell scripts that are executed. .Pp Since functions are executed in the current shell environment, parameter assignments made inside functions are visible after the function completes. If this is not the desired effect, the .Ic typeset -command can be used inside a function to create a local parameter. Note that -special parameters (e.g., $$, $\&!) can't be scoped in this way. +command can be used inside a function to create a local parameter. +Note that special parameters (e.g., $$, $\&!) can't be scoped in this way. .Pp The exit status of a function is that of the last command executed in the -function. A function can be made to finish immediately using the +function. +A function can be made to finish immediately using the .Ic return command; this may also be used to explicitly specify the exit status. .Pp @@ -1703,12 +1794,13 @@ untouched, so using .Ic getopts inside a function interferes with using .Ic getopts -outside the function). In the future, the following differences will also be -added: +outside the function). +In the future, the following differences will also be added: .Bl -bullet -offset indent .It A separate trap/signal environment will be used during the execution of -functions. This will mean that traps set inside a function will not affect the +functions. +This will mean that traps set inside a function will not affect the shell's traps and signals that are not ignored in the shell (but may be trapped) will have their default effect in a function. .It @@ -1722,14 +1814,15 @@ The shell is intended to be compliant; however, in some cases, .Tn POSIX behaviour is contrary either to the original Korn shell behaviour or to user -convenience. How the shell behaves in these cases is determined by the state -of the +convenience. +How the shell behaves in these cases is determined by the state of the .Ic posix option .Pq Ic set Fl o Ic posix . If it is on, the .Tn POSIX -behaviour is followed; otherwise, it is not. The +behaviour is followed; otherwise, it is not. +The .Ic posix option is set automatically when the shell starts up if the environment contains the @@ -1755,15 +1848,16 @@ Occurrences of .Ic \e\&" inside double quoted .Ic `\&.\&.` -command substitutions. In +command substitutions. +In .Tn POSIX mode, the .Ic \e\&" is interpreted when the command is interpreted; in .Pf non- Tn POSIX mode, the -backslash is stripped before the command substitution is interpreted. For -example, +backslash is stripped before the command substitution is interpreted. +For example, .Ic echo \&"`echo \e\&"hi\e\&"`\&" produces .Dq \&"hi\&" @@ -1773,25 +1867,28 @@ mode, .Dq hi in .Pf non- Tn POSIX -mode. To avoid problems, use the +mode. +To avoid problems, use the .Ic $(...) form of command substitution. .It .Ic kill -l -output. In +output. +In .Tn POSIX mode, signal names are listed one per line; in .Pf non- Tn POSIX mode, -signal numbers, names and descriptions are printed in columns. In future, a new -option +signal numbers, names and descriptions are printed in columns. +In future, a new option .Po Fl v \ perhaps .Pc will be added to distinguish the two behaviours. .It .Ic fg -exit status. In +exit status. +In .Tn POSIX mode, the exit status is 0 if no errors occur; in .Pf non- Tn POSIX @@ -1809,18 +1906,20 @@ mode, options can start with either or .Ql + . .It -Brace expansion (also known as alternation). In +Brace expansion (also known as alternation). +In .Tn POSIX mode, brace expansion is disabled; in .Pf non- Tn POSIX -mode, brace expansion is enabled. Note that +mode, brace expansion is enabled. +Note that .Ic set Fl o Ic posix (or setting the .Ev POSIXLY_CORRECT parameter) automatically turns the .Ic braceexpand -option off, although it can be explicitly turned on later. +option off; however, it can be explicitly turned on later. .It .Ic set \&- . In @@ -1834,7 +1933,8 @@ options; in mode, it does. .It .Ic set -exit status. In +exit status. +In .Tn POSIX mode, the exit status of .Ic set @@ -1843,13 +1943,15 @@ is 0 if there are no errors; in mode, the exit status is that of any command substitutions performed in generating the .Ic set -command. For example, +command. +For example, .Ic set \&-\&- `false`; echo $? prints 0 in .Tn POSIX mode, 1 in .Pf non- Tn POSIX -mode. This construct is used in most shell scripts that use the old +mode. +This construct is used in most shell scripts that use the old .Xr getopt 1 command. .It @@ -1859,7 +1961,8 @@ Argument expansion of .Ic readonly , and .Ic typeset -commands. In +commands. +In .Tn POSIX mode, normal argument expansion is done; in .Pf non- Tn POSIX @@ -1867,7 +1970,8 @@ mode, field splitting, file globbing, brace expansion, and (normal) tilde expansion are turned off, while assignment tilde expansion is turned on. .It -Signal specification. In +Signal specification. +In .Tn POSIX mode, signals can be specified as digits, only if signal numbers match @@ -1877,13 +1981,15 @@ KILL=9, ALRM=14, and TERM=15); in .Pf non- Tn POSIX mode, signals can always be digits. .It -Alias expansion. In +Alias expansion. +In .Tn POSIX mode, alias expansion is only carried out when reading command words; in .Pf non- Tn POSIX mode, alias expansion is carried out on any -word following an alias that ended in a space. For example, the following +word following an alias that ended in a space. +For example, the following .Ic for loop .Pp @@ -1904,7 +2010,8 @@ in .Pf non- Tn POSIX mode. .It -Test. In +Test. +In .Tn POSIX mode, the expression .Ql Fl t @@ -1920,27 +2027,30 @@ test may be left out and defaults to 1). .El .Ss Command execution After evaluation of command-line arguments, redirections and parameter -assignments, the type of command is determined: a special built-in, a +assignments, the type of command is determined: a special built-in, a function, a regular built-in, or the name of a file to execute found using the .Ev PATH -parameter. The checks are made in the above order. Special built-in commands -differ from other commands in that the +parameter. +The checks are made in the above order. +Special built-in commands differ from other commands in that the .Ev PATH parameter is not used to find them, and an error during their execution can cause a non-interactive shell to exit and parameter assignments that are -specified before the command are kept after the command completes. Just to -confuse things, if the +specified before the command are kept after the command completes. +Just to confuse things, if the .Ic posix option is turned off (see .Ic set command below), some special commands are very special in that no field splitting, file globbing, brace expansion, nor tilde expansion is performed -on arguments that look like assignments. Regular built-in commands are -different only in that the +on arguments that look like assignments. +Regular built-in commands are different only in that the .Ev PATH parameter is not used to find them. .Pp -The original ksh and +The original +.Nm ksh +and .Tn POSIX differ somewhat in which commands are considered special or regular: @@ -1985,15 +2095,18 @@ The following described the special and regular built-in commands: .It Ic \&. Ar file Op Ar arg1 ... Execute the commands in .Ar file -in the current environment. The file is searched for in the directories of +in the current environment. +The file is searched for in the directories of .Ev PATH . If arguments are given, the positional parameters may be used to access them while .Ar file -is being executed. If no arguments are given, the positional parameters are +is being executed. +If no arguments are given, the positional parameters are those of the environment the command is used in. .It Ic \&: Op Ar ... -The null command. Exit status is set to zero. +The null command. +Exit status is set to zero. .It Xo Ic alias .Op Fl d | Ic +-t Op Fl r .Op Ic +-px @@ -2005,21 +2118,26 @@ The null command. Exit status is set to zero. .Xc Without arguments, .Ic alias -lists all aliases. For any name without a value, the existing alias is listed. +lists all aliases. +For any name without a value, the existing alias is listed. Any name with a value defines an alias (see .Sx Aliases above). .Pp -When listing aliases, one of two formats is used. Normally, aliases are listed -as +When listing aliases, one of two formats is used. +Normally, aliases are listed as .Ar name Ns No = Ar value , where .Ar value -is quoted. If options were preceded with +is quoted. +If options were preceded with .Ql + , -or a lone \&+ is given on the command line, only +or a lone +.Ql + +is given on the command line, only .Ar name -is printed. In addition, if the +is printed. +In addition, if the .Fl p option is used, each alias is prefixed with the string .Dq alias\ \& . @@ -2036,7 +2154,8 @@ with the export attribute (exporting an alias has no effect). The .Fl t option indicates that tracked aliases are to be listed/set (values specified on -the command line are ignored for tracked aliases). The +the command line are ignored for tracked aliases). +The .Fl r option indicates that all tracked aliases are to be reset. .Pp @@ -2047,11 +2166,11 @@ listed or set (see .Sx Tilde expansion above). .It Ic bg Op Ar job ... -Resume the specified stopped job(s) in the background. If no jobs are -specified, +Resume the specified stopped job(s) in the background. +If no jobs are specified, .Ic %\&+ -is assumed. This command is only available on systems which support job -control (see +is assumed. +This command is only available on systems which support job control (see .Sx Job control below for more information). .It Xo Ic bind Op Fl m @@ -2088,7 +2207,8 @@ is set, it lists the search path for the directory containing .Ar dir . A .Dv NULL -path means the current directory. If +path means the current directory. +If .Ar dir is found in any component of the .Ev CDPATH @@ -2099,13 +2219,15 @@ If .Ar dir is missing, the home directory .Ev HOME -is used. If +is used. +If .Ar dir is .Ql - , the previous working directory is used (see .Ev OLDPWD -parameter). If the +parameter). +If the .Fl L option (logical path) is used or if the .Ic physical @@ -2115,13 +2237,15 @@ command below) isn't set, references to .Dq \&.\&. in .Ar dir -are relative to the path used to get to the directory. If the +are relative to the path used to get to the directory. +If the .Fl P option (physical path) is used or if the .Ic physical option is set, .Dq \&.\&. -is relative to the filesystem directory tree. The +is relative to the filesystem directory tree. +The .Ev PWD and .Ev OLDPWD @@ -2142,15 +2266,17 @@ directory. .Ar cmd is executed exactly as if .Ic command -had not been specified, with two exceptions. First, +had not been specified, with two exceptions. +First, .Ar cmd cannot be a shell function, and second, special built-in commands lose their specialness (i.e., redirection and utility errors do not cause the shell to -exit, and command assignments are not permanent). If the +exit, and command assignments are not permanent). +If the .Fl p option is given, a default search path is used instead of the current value of .Ev PATH -(the actual value of the default path is system dependent: on POSIXish +(the actual value of the default path is system dependent: on POSIXish systems, it is the value returned by .Ic getconf CS_PATH ) . .It Ic continue Op Ar level @@ -2168,7 +2294,8 @@ defaults to 1. .Op Ar arg ... .Xc Prints its arguments (separated by spaces) followed by a newline, to the -standard output. The newline is suppressed if any of the arguments contain the +standard output. +The newline is suppressed if any of the arguments contain the backslash sequence .Ql \ec . See the @@ -2177,7 +2304,8 @@ command below for a list of other backslash sequences that are recognized. .Pp The options are provided for compatibility with .Bx -shell scripts. The +shell scripts. +The .Fl n option suppresses the trailing newline, .Fl e @@ -2194,12 +2322,14 @@ The command is executed without forking, replacing the shell process. .Pp If no command is given except for I/O redirection, the I/O redirection is permanent and the shell is -not replaced. Any file descriptors which are opened or +not replaced. +Any file descriptors which are opened or .Xr dup 2 Ns No 'd in this way are made available to other executed commands (note that the Korn shell differs here: it does not pass on file descriptors greater than 2). .It Ic exit Op Ar status -The shell exits with the specified exit status. If +The shell exits with the specified exit status. +If .Ar status is not specified, the exit status is the current value of the .Ic \&? @@ -2207,9 +2337,9 @@ parameter. .It Xo Ic export Op Fl p .Op Ar parameter Ns Op \&= Ns Ar value .Xc -Sets the export attribute of the named parameters. Exported parameters are -passed in the environment to executed commands. If values are specified, the -named parameters are also assigned. +Sets the export attribute of the named parameters. +Exported parameters are passed in the environment to executed commands. +If values are specified, the named parameters are also assigned. .Pp If no parameters are specified, the names of all parameters with the export attribute are printed one per line, unless the @@ -2239,10 +2369,11 @@ are replaced with This command is usually accessed with the predefined .Ic alias r='fx -e -' . .It Ic fg Op Ar job ... -Resume the specified job(s) in the foreground. If no jobs are specified, +Resume the specified job(s) in the foreground. +If no jobs are specified, .Ic %\&+ -is assumed. This command is only available on systems which support job -control (see +is assumed. +This command is only available on systems which support job control (see .Sx Job control below for more information). .It Xo Ic getopts Ar optstring name @@ -2253,9 +2384,11 @@ parameters, if no arguments are given) and to check for legal options. .Ar optstring contains the option letters that .Ic getopts -is to recognize. If a letter is followed by a colon, the option is expected to -have an argument. Options that do not take arguments may be grouped in a single -argument. If an option takes an argument and the option character is not the +is to recognize. +If a letter is followed by a colon, the option is expected to +have an argument. +Options that do not take arguments may be grouped in a single argument. +If an option takes an argument and the option character is not the last character of the argument it is found in, the remainder of the argument is taken to be the option's argument; otherwise, the next argument is the option's argument. @@ -2281,14 +2414,15 @@ mark or a colon is placed in .Ar name (indicating an illegal option or missing argument, respectively) and .Ev OPTAG -is set to the option character that caused the problem. An error message is -also printed to standard error if +is set to the option character that caused the problem. +An error message is also printed to standard error if .Ar optstring does not being with a colon. .Pp When the end of the options is encountered, .Ic getopts -exits with a non-zero exit status. Options end at the first (non-option +exits with a non-zero exit status. +Options end at the first (non-option argument) argument that does not start with a .Ql - , or when a @@ -2309,9 +2443,11 @@ may lead to unexpected results. .It Xo Ic hash Op Fl r .Op Ar name ... .Xc -Without arguments, any hashed executable command pathnames are listed. The +Without arguments, any hashed executable command pathnames are listed. +The .Fl r -option causes all hashed commands to be removed from the hash table. Each +option causes all hashed commands to be removed from the hash table. +Each .Ar name is searched as if it were a command name and added to the hash table if it is an executable command. @@ -2319,14 +2455,18 @@ an executable command. .Op Ar job ... .Xc Display information about the specified job(s); if no jobs are specified, all -jobs are displayed. The +jobs are displayed. +The .Fl n option causes information to be displayed only for jobs that have changed -state since the last notification. If the +state since the last notification. +If the .Fl l -option is used, the process ID of each process in a job is also listed. The +option is used, the process ID of each process in a job is also listed. +The .Fl p -option causes only the process group of each job to be printed. See +option causes only the process group of each job to be printed. +See .Sx Job control below for the format of .Ar job @@ -2339,10 +2479,12 @@ and the displayed job. .Ar pgrp No } Ar ... .Xc Send the specified signal to the specified jobs, process IDs, or process -groups. If no signal is specified, the +groups. +If no signal is specified, the .Dv TERM -signal is sent. If a job is specified, the signal is sent to the job's -process group. See +signal is sent. +If a job is specified, the signal is sent to the job's process group. +See .Sx Job control below for the format of .Ar job . @@ -2359,9 +2501,11 @@ a short description of them are printed. .Xc .Ic print prints its arguments on the standard output, separated by spaces and -terminated with a newline. The +terminated with a newline. +The .Fl n -option suppresses the newline. By default, certain C escapes are translated. +option suppresses the newline. +By default, certain C escapes are translated. These include .Ql \eb , .Ql \ef , @@ -2382,7 +2526,8 @@ option. .Ql \e expansion may be inhibited with the .Fl r -option. The +option. +The .Fl s option prints to the history file instead of standard output, the .Fl u @@ -2407,11 +2552,13 @@ command, which does not process .Ql \e sequences unless the .Fl e -option is given. As above, the +option is given. +As above, the .Fl n option suppresses the trailing newline. .It Ic pwd Op Fl LP -Print the present working directory. If the +Print the present working directory. +If the .Fl L option is used or if the .Ic physical @@ -2419,7 +2566,8 @@ option (see .Ic set command below) isn't set, the logical path is printed (i.e., the path used to .Ic cd -to the current directory). If the +to the current directory). +If the .Fl P option (physical path) is used or if the .Ic physical @@ -2434,17 +2582,19 @@ using the .Ev IFS parameter (see .Sx Substitution -above), and assigns each field to the specified parameters. If there are more -parameters than fields, the extra parameters are set to +above), and assigns each field to the specified parameters. +If there are more parameters than fields, the extra parameters are set to .Dv NULL , or alternatively, if there are more fields than parameters, the last parameter -is assigned the remaining fields (inclusive of any separating spaces). If no -parameters are specified, the +is assigned the remaining fields (inclusive of any separating spaces). +If no parameters are specified, the .Ev REPLY -parameter is used. If the input line ends in a backslash and the +parameter is used. +If the input line ends in a backslash and the .Fl r option was not used, the backslash and the newline are stripped and more input -is read. If no input is read, +is read. +If no input is read, .Ic read exits with a non-zero status. .Pp @@ -2461,7 +2611,8 @@ options cause input to be read from file descriptor .Ar n or the current co-process (see .Sx Co-processes -above for comments on this), respectively. If the +above for comments on this), respectively. +If the .Fl s option is used, input is saved to the history file. .It Xo Ic readonly Op Fl p @@ -2469,8 +2620,10 @@ option is used, input is saved to the history file. .Op Ns = Ns Ar value .Ar ... Oc .Xc -Sets the read-only attribute of the named parameters. If values are given, -parameters are set to them before setting the attribute. Once a parameter is +Sets the read-only attribute of the named parameters. +If values are given, +parameters are set to them before setting the attribute. +Once a parameter is made read-only, it cannot be unset and its value cannot be changed. .Pp If no parameters are specified, the names of all parameters with the read-only @@ -2487,8 +2640,8 @@ script, with exit status .Ar status . If no .Ar status -is given, the exit status of the last executed command is used. If used -outside of a function or +is given, the exit status of the last executed command is used. +If used outside of a function or .Ic \&. script, it has the same effect as .Ic exit . @@ -2540,7 +2693,8 @@ the rest are left untouched. All new parameters are created with the export attribute. .It Fl b Ic notify Print job notification messages asynchronously, instead of just before the -prompt. Only used if job control is enabled +prompt. +Only used if job control is enabled .Pq Fl m . .It Fl C Ic noclobber Prevent @@ -2554,7 +2708,8 @@ must be used to force an overwrite Exit (after executing the .Dv ERR trap) as soon as an error occurs or a command fails (i.e., exits with a -non-zero status). This does not apply to commands whose exit status is +non-zero status). +This does not apply to commands whose exit status is explicitly tested by a shell construct such as .Ic if , .Ic until , @@ -2568,34 +2723,39 @@ Do not expand file name patterns. .It Fl h Ic trackall Create tracked aliases for all executed commands (see .Sx Aliases -above). Enabled by default for non-interactive shells. +above). +Enabled by default for non-interactive shells. .It Fl i Ic interactive -Enable interactive mode. This can only be set/unset when the shell is invoked. +Enable interactive mode. +This can only be set/unset when the shell is invoked. .It Fl k Ic keyword Parameter assignments are recognized anywhere in a command. .It Fl l Ic login -The shell is a login shell. This can only be set/unset when the shell is -invoked (see +The shell is a login shell. +This can only be set/unset when the shell is invoked (see .Sx Shell startup above). .It Fl m Ic monitor Enable job control (default for interactive shells). .It Fl n lc noexec -Do not execute any commands. Useful for checking the syntax of scripts +Do not execute any commands. +Useful for checking the syntax of scripts (ignored if interactive). .It Fl p Ic privileged Set automatically if, when the shell starts, the read UID or GID does not match -the effective UID (EUID) or GID (EGID), respectively. See +the effective UID (EUID) or GID (EGID), respectively. +See .Sx Shell startup above for a description of what this means. .It Fl r Ic restricted -Enable restricted mode. This option can only be used when the shell is invoked. +Enable restricted mode. +This option can only be used when the shell is invoked. See .Sx Shell startup above for a description of what this means. .It Fl s Ic stdin -If used where the shell is invoked, commands are read from standard input. Set -automatically if the shell is invoked with no arguments. +If used where the shell is invoked, commands are read from standard input. +Set automatically if the shell is invoked with no arguments. .Pp When .Fl s @@ -2633,13 +2793,15 @@ must be used. .It Ic nohup Do not kill running jobs with a .Dv HUP -signal when a login shell exists. Currently set by default, but this will +signal when a login shell exists. +Currently set by default, but this will change in the future to be compatible with the original Korn shell (which doesn't have this option, but does send the .Dv HUP signal). .It Ic nolog -No effect. In the original Korn shell, this prevents function definitions from +No effect. +In the original Korn shell, this prevents function definitions from being stored in the history file. .It Ic physical Causes the @@ -2654,9 +2816,9 @@ directories instead of .Dq logical directories (i.e., the shell handles .Dq \&.\&. , -which allows the user to be oblivious of symbolic links to directories). Clear -by default. Note that setting this option does not affect the current value of -the +which allows the user to be oblivious of symbolic links to directories). +Clear by default. +Note that setting this option does not affect the current value of the .Ev PWD parameter; only the .Ic cd @@ -2670,13 +2832,15 @@ commands above for more details. .It Ic posix Enable .Tn POSIX -mode. See +mode. +See .Sx POSIX mode above. .It Ic vi Enable vi-like command-line editing (interactive shells only). .It Ic viraw -No effect. In the original Korn shell, unless +No effect. +In the original Korn shell, unless .Ic viraw was set, the vi command-line mode would let the tty driver do the work until .Tn ESC @@ -2696,7 +2860,8 @@ In vi command-line editing, do command and file name completion when tab (^I) is entered in insert mode. .El .Pp -These options can also be used upon invocation of the shell. The current set of +These options can also be used upon invocation of the shell. +The current set of options (with single letter names) can be found in the parameter .Dv \&- . .Ic set Fl o @@ -2705,11 +2870,12 @@ with no option name will list all the options and whether each is on or off; will print the long names of all options that are currently on. .Pp Remaining arguments, if any, are positional parameters and are assigned, in -order, to the positional parameters (i.e., $1, $2, etc.). If options end with +order, to the positional parameters (i.e., $1, $2, etc.). +If options end with .Ql -- -and there are no remaining arguments, all positional parameters are cleared. If -no options or arguments are given, the values of all names are printed. For -unknown historical reasons, a lone +and there are no remaining arguments, all positional parameters are cleared. +If no options or arguments are given, the values of all names are printed. +For unknown historical reasons, a lone .Ql - option is treated specially -- it clears both the .Fl x @@ -2732,15 +2898,18 @@ defaults to 1. evaluates the .Ar expression and returns zero status if true, 1 status if false, or greater than 1 if there -was an error. It is normally used as the condition command of +was an error. +It is normally used as the condition command of .Ic if and .Ic while -statements. The following basic expressions are available: +statements. +The following basic expressions are available: .Bl -tag -width 17n .It Ar str .Ar str -has non-zero length. Note that there is the potential for problems if +has non-zero length. +Note that there is the potential for problems if .Ar str turns out to be an operator (e.g., .Fl r ) . @@ -2816,8 +2985,8 @@ Shell .Ar option is set (see .Ic set -command above for a list of options). As a non-standard extension, if the -option starts with a +command above for a list of options). +As a non-standard extension, if the option starts with a .Ql ! , the test is negated; the test always fails if .Ar option @@ -2845,7 +3014,8 @@ is the same file as second .It Fl t Op Ar fd File descriptor .Ar fd -is a tty device. If the +is a tty device. +If the .Ic posix option is not set, .Ar fd @@ -2906,7 +3076,8 @@ is a file descriptor number), the .Ic test command will attempt to fake it for all tests that operate on files (except the .Fl e -test). For example, +test). +For example, .Ic \&[ -w /dev/fd/2 \&] tests if file descriptor 2 is writable. .Pp @@ -2969,7 +3140,8 @@ or .Dv ALRM ) or the number of the signal (see .Ic kill -l -command above). There are two special signals: +command above). +There are two special signals: .Dv EXIT (also known as 0), which is executed when the shell is about to exit, and .Dv ERR , @@ -2982,7 +3154,8 @@ option were see -- see .Ic set command above). .Dv EXIT -handlers are executed in the environment of the last executed command. Note +handlers are executed in the environment of the last executed command. +Note that for non-interactive shells, the trap handler cannot be changed for signals that were ignored when the shell started. .Pp @@ -3013,7 +3186,8 @@ A command that exits with a zero value. .Op Ns = Ns Ar value .Ar ... Oc .Xc -Display or set parameter attributes. With no +Display or set parameter attributes. +With no .Ar name arguments, parameter attributes are displayed; if no options are used, the current attributes of all parameters are printed as @@ -3031,7 +3205,8 @@ arguments are given, the attributes of the named parameters are set .Pq Ic \&- or cleared .Pq Ic \&+ . -Values for parameters may optionally be specified. If +Values for parameters may optionally be specified. +If .Ic typeset is used inside a function, any newly created parameters are local to the function. @@ -3040,7 +3215,8 @@ When .Fl f is used, .Ic typeset -operates on the attributes of functions. As with parameters, if no +operates on the attributes of functions. +As with parameters, if no .Ar name Ns s are given, functions are listed with their values (i.e., definitions) unless options are introduced with @@ -3050,22 +3226,27 @@ in which case only the function names are reported. .It Fl L Ns Ar n Left justify attribute. .Ar n -specifies the field width. If +specifies the field width. +If .Ar n is not specified, the current width of a parameter (or the width of its first -assigned value) is used. Leading whitespace (and zeros, if used with the +assigned value) is used. +Leading whitespace (and zeros, if used with the .Fl Z -option) is stripped. If necessary, values are either truncated or space padded +option) is stripped. +If necessary, values are either truncated or space padded to fit the field width. .It Fl R Ns Ar n Right justify attribute. .Ar n -specifies the field width. If +specifies the field width. +If .Ar n is not specified, the current width of a parameter (or the width of its first -assigned value) is used. Trailing whitespace is stripped. If necessary, values -are either stripped of leading characters or space padded to make them fit the -field width. +assigned value) is used. +Trailing whitespace is stripped. +If necessary, values are either stripped of leading characters or space +padded to make them fit the field width. .It Fl Z Ns Ar n Zero fill attribute. If not combined with .Fl L , @@ -3076,19 +3257,23 @@ except zero padding is used instead of space padding. Integer attribute. .Ar n specifies the base to use when displaying the integer (if not specified, the -base given in the first assignment is used). Parameters with this attribute may +base given in the first assignment is used). +Parameters with this attribute may be assigned values containing arithmetic expressions. .It Fl U -Unsigned integer attribute. Integers are printed as unsigned values (only +Unsigned integer attribute. +Integers are printed as unsigned values (only useful when combined with the .Fl i -option). This option is not in the original Korn shell. +option). +This option is not in the original Korn shell. .It Fl f -Function mode. Display or set functions and their attributes, instead of -parameters. +Function mode. +Display or set functions and their attributes, instead of parameters. .It Fl l -Lower case attribute. All upper case characters in values are converted to -lower case. (In the original Korn shell, this parameter meant +Lower case attribute. +All upper case characters in values are converted to lower case. +(In the original Korn shell, this parameter meant .Dq long integer when used with the .Fl i @@ -3097,52 +3282,63 @@ option.) Print complete .Ic typeset commands that can be used to re-create the attributes (but not the values) or -parameters. This is the default action (option exists for ksh93 compatibility). +parameters. +This is the default action (option exists for ksh93 compatibility). .It Fl r -Read-only attribute. Parameters with this attribute may not be assigned to or -unset. Once this attribute is set, it can not be turned off. +Read-only attribute. +Parameters with this attribute may not be assigned to or unset. +Once this attribute is set, it can not be turned off. .It Fl t -Tag attribute. Has no meaning to the shell; provided for application use. +Tag attribute. +Has no meaning to the shell; provided for application use. .Pp For functions, .Fl t -is the trace attribute. When functions with the trace attribute are executed, -the +is the trace attribute. +When functions with the trace attribute are executed, the .Ic xtrace .Pq Fl x shell option is temporarily turned on. .It Fl u -Upper case attribute. All lower case characters in values are converted to -upper case. (In the original Korn shell, this parameter meant +Upper case attribute. +All lower case characters in values are converted to upper case. +(In the original Korn shell, this parameter meant .Dq unsigned integer when used with the .Fl i option, which meant upper case letters would never be used for bases greater -than 10. See the +than 10. +See the .Fl U option.) .Pp For functions, .Fl u -is the undefined attribute. See +is the undefined attribute. +See .Sx Functions above for the implications of this. .It Fl x -Export attribute. Parameters (or functions) are placed in the environment of -any executed commands. Exported functions are not yet implemented. +Export attribute. +Parameters (or functions) are placed in the environment of +any executed commands. +Exported functions are not yet implemented. .El .It Xo Ic ulimit Op Fl acdfHlmnpsStvw .Op Ar value .Xc -Display or set process limits. If no options are used, the file size limit +Display or set process limits. +If no options are used, the file size limit .Pq Fl f is assumed. .Ar value , if specified, may be either an arithmetic expression or the word .Dq unlimited . The limits affect the shell and any processes created by the shell after a -limit is imposed. Note that some systems may not allow limits to be increased -once they are set. Also note that the types of limits available are system +limit is imposed. +Note that some systems may not allow limits to be increased +once they are set. +Also note that the types of limits available are system dependent -- some systems have only the .Fl f limit. @@ -3229,9 +3425,11 @@ and is equivalent (on most systems) to the octal mask .It Xo Ic unalias Op Fl adt .Op Ar name1 ... .Xc -The aliases for the given names are removed. If the +The aliases for the given names are removed. +If the .Fl a -option is used, all aliases are removed. If the +option is used, all aliases are removed. +If the .Fl t or .Fl d @@ -3250,7 +3448,8 @@ or functions The exit status is non-zero if any of the parameters were already unset, zero otherwise. .It Ic wait Op Ar job ... -Wait for the specified job(s) to finish. The exit status of +Wait for the specified job(s) to finish. +The exit status of .Ic wait is that of the last specified job; if the last job is killed by a signal, the exit status is 128 + the number of the signal (see @@ -3258,7 +3457,8 @@ exit status is 128 + the number of the signal (see above); if the last specified job can't be found (because it never existed, or had already finished), the exit status of .Ic wait -is 127. See +is 127. +See .Sx Job control below for the format of .Ar job . @@ -3273,7 +3473,8 @@ signal is received. If no jobs are specified, .Ic wait waits for all currently running jobs (if any) to finish and exits with a zero -status. If job monitoring is enabled, the completion status of jobs is printed +status. +If job monitoring is enabled, the completion status of jobs is printed (this is not the case when jobs are explicitly specified). .It Xo Ic whence Op Fl pv .Op Ar name ... @@ -3281,11 +3482,13 @@ status. If job monitoring is enabled, the completion status of jobs is printed For each .Ar name , the type of command is listed (reserved word, built-in, alias, -function, tracked alias, or executable). If the +function, tracked alias, or executable). +If the .Fl p option is used, a path search is performed even if .Ar name -is a reserved word, alias, etc. Without the +is a reserved word, alias, etc. +Without the .Fl v option, .Ic whence @@ -3293,7 +3496,8 @@ is similar to .Ic command Fl v except that .Ic whence -will find reserved words and won't print aliases as alias commands. With the +will find reserved words and won't print aliases as alias commands. +With the .Fl v option, .Ic whence @@ -3310,17 +3514,19 @@ status is non-zero. .El .Ss Job control Job control refers to the shell's ability to monitor and control jobs, which -are processes or groups of processes created for commands or pipelines. At a -minimum, the shell keeps track of the status of the background (i.e., +are processes or groups of processes created for commands or pipelines. +At a minimum, the shell keeps track of the status of the background (i.e., asynchronous) jobs that currently exist; this information can be displayed using the .Ic jobs -commands. If job control is fully enabled (using +commands. +If job control is fully enabled (using .Ic set Fl m or .Ic set Fl o Ic monitor ) , as it is for interactive shells, the processes of a job are placed in their -own process group. Foreground jobs can be stopped by typing the suspend +own process group. +Foreground jobs can be stopped by typing the suspend character from the terminal (normally ^Z), jobs can be restarted in either the foreground or background using the .Ic fg @@ -3335,11 +3541,12 @@ commands like .Ic read cannot be. .Pp -When a job is created, it is assigned a job number. For interactive shells, -this number is printed inside +When a job is created, it is assigned a job number. +For interactive shells, this number is printed inside .Dq \&[..\&] , followed by the process IDs of the processes in the job when an asynchronous -command is run. A job may be referred to in +command is run. +A job may be referred to in .Ic bg , .Ic fg , .Ic jobs , @@ -3412,12 +3619,14 @@ The job was stopped by the indicated .It Ar signal-description Op Dq core dumped The job was killed by a signal (e.g., memory fault, hangup, etc.; use .Ic kill -l -for a list of signal descriptions). The +for a list of signal descriptions). +The .Dq core dumped message indicates the process created a core file. .El .It Ar command -is the command that created the process. If there are multiple processes in +is the command that created the process. +If there are multiple processes in the job, each process will have a line showing its .Ar command and possibly its @@ -3430,10 +3639,12 @@ state, the shell warns the user that there are stopped jobs and does not exit. If another attempt is immediately made to exit the shell, the stopped jobs are sent a .Dv HUP -signal and the shell exits. Similarly, if the +signal and the shell exits. +Similarly, if the .Ic nohup option is not set and there are running jobs when an attempt is made to exit -a login shell, the shell warns the user and does not exit. If another attempt +a login shell, the shell warns the user and does not exit. +If another attempt is immediately made to exit the shell, the running jobs are sent a .Dv HUP signal and the shell exits. @@ -3490,7 +3701,8 @@ is implemented as a run-time option of with only those .Nm ksh features whose syntax or semantics are incompatible with a traditional Bourne -shell disabled. Since this leaves some +shell disabled. +Since this leaves some .Nm ksh extensions exposed, caution should be used where backwards compatibility with traditional Bourne or @@ -3499,7 +3711,8 @@ compliant shells is an issue. .Sh BUGS Any bugs in .Nm pdksh -should be reported to pdksh@cs.mun.ca. Please include the version of +should be reported to pdksh@cs.mun.ca. +Please include the version of .Nm pdksh .Po .Ic echo $KSH_VERSION @@ -3516,7 +3729,8 @@ and a copy of your .Pa config.h (the file generated by the .Pa configure -script). New version of +script). +New versions of .Nm pdksh can be obtained from ftp://ftp.cs.mun.ca/pub/pdksh. .Pp @@ -3529,11 +3743,13 @@ I'm aware of this and there is no need to report it. .Sh AUTHORS This shell is based on the public domain 7th edition Bourne shell clone by Charles Forsyth and parts of the BRL shell by Doug A. Gwyn, Doug Kingston, -Ron Natalie, Arnold Robbins, Lou Salkind, and others. The first release of +Ron Natalie, Arnold Robbins, Lou Salkind, and others. +The first release of .Nm pdksh was created by Eric Gisin, and it was subsequently maintained by John R. MacMillan (change!john@sq.sq.com) and Simon J. Gerraty (sjg@zen.void.oz.au). -The current maintainer is Michael Rendell (michael@cs.mun.ca). The +The current maintainer is Michael Rendell (michael@cs.mun.ca). +The .Pa CONTRIBUTORS file in the source distribution contains a more complete list of people and their part in the shell's development. |