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Diffstat (limited to 'bin/csh/USD.doc/csh.g')
| -rw-r--r-- | bin/csh/USD.doc/csh.g | 603 |
1 files changed, 304 insertions, 299 deletions
diff --git a/bin/csh/USD.doc/csh.g b/bin/csh/USD.doc/csh.g index d06ecbf4214..ddcb2ed4588 100644 --- a/bin/csh/USD.doc/csh.g +++ b/bin/csh/USD.doc/csh.g @@ -1,4 +1,4 @@ -.\" $OpenBSD: csh.g,v 1.5 2003/06/02 23:32:07 millert Exp $ +.\" $OpenBSD: csh.g,v 1.6 2004/04/21 08:11:15 jmc Exp $ .\" $NetBSD: csh.g,v 1.3 1995/03/21 09:03:42 cgd Exp $ .\" .\" Copyright (c) 1980, 1993 @@ -38,7 +38,7 @@ introduction to the shell and gives references to sections of the shell document for further information about them. References of the form -`pr (1)' +pr(1) indicate that the command .I pr is in the \s-2UNIX\s0 User Reference manual in section 1. @@ -52,23 +52,22 @@ manual. .IP \&\fB.\fR 15n Your current directory has the name `.' as well as the name printed by the command -.I pwd; +.I pwd ; see also -.I dirs. -The current directory `.' is usually the first -.I component +.I dirs . +The current directory `.' is usually included as a +.I component of the search path contained in the variable -.I path , -thus commands which are in `.' are found first (2.2). -The character `.' is also used in separating -.I components +.I path . +The character `.' is also used in separating +.I components of filenames (1.6). -The character `.' at the beginning of a -.I component -of a -.I pathname -is treated specially and not matched by the +The character `.' at the beginning of a +.I component +of a +.I pathname +is treated specially and not matched by the .I "filename expansion" metacharacters `?', `*', and `[' `]' pairs (1.6). .IP \&\fB..\fR @@ -89,22 +88,22 @@ The current directory is printed by (2.7). .IP a.out Compilers which create executable images create them, by default, in the -file -.I a.out. +file +.I a.out . for historical reasons (2.3). .IP "absolute pathname" .br -A -.I pathname +A +.I pathname which begins with a `/' is .I absolute -since it specifies the -.I path +since it specifies the +.I path of directories from the beginning of the entire directory system \- called the .I root -directory. -.I Pathname s +directory. +.I Pathname s which are not .I absolute are called @@ -120,17 +119,17 @@ command, or a transformation on a command to be performed in the shell. The shell has a command .I alias -which establishes -.I aliases +which establishes +.I aliases and can print their current values. The command .I unalias -is used to remove -.I aliases +is used to remove +.I aliases (2.4). .IP argument -Commands in \s-2UNIX\s0 receive a list of -.I argument +Commands in \s-2UNIX\s0 receive a list of +.I argument words. Thus the command .DS @@ -138,11 +137,11 @@ echo a b c .DE consists of the .I "command name" -`echo' and three -.I argument +`echo' and three +.I argument words `a', `b' and `c'. -The set of -.I arguments +The set of +.I arguments after the .I "command name" is said to be the @@ -162,39 +161,40 @@ commands (2.6). .IP base A filename is sometimes thought of as consisting of a .I base -part, before any `.' character, and an -.I extension +part, before any `.' character, and an +.I extension \- the part after the `.'. See .I filename and .I extension -(1.6) and basename (1). +(1.6) and basename(1). .IP bg The .I bg command causes a -.I suspended +.I suspended job to continue execution in the .I background (2.6). .IP bin A directory containing binaries of programs and shell scripts to be -executed is typically called a -.I bin +executed is typically called a +.I bin directory. -The standard system -.I bin +The standard system +.I bin directories are `/bin' containing the most heavily used commands and `/usr/bin' which contains most other user programs. -Programs developed at UC Berkeley live in `/usr/ucb', while locally -written programs live in `/usr/local'. Games are kept in the directory -`/usr/games'. +.\" Programs developed at UC Berkeley live in `/usr/ucb', while locally +.\" written programs live in `/usr/local'. +Locally written programs live in `/usr/local/bin'. +Games are kept in the directory `/usr/games'. You can place binaries in any directory. If you wish to execute them often, the name of the directories -should be a -.I component +should be a +.I component of the variable .I path . .IP break @@ -214,8 +214,8 @@ A command executed directly by the shell is called a .I builtin command. Most commands in \s-2UNIX\s0 are not built into the shell, -but rather exist as files in -.I bin +but rather exist as files in +.I bin directories. These commands are accessible because the directories in which they reside are named in the @@ -228,23 +228,23 @@ command is used as a label in a .I switch statement in the shell's control structure, similar to that of the language C. -Details are given in the shell documentation `csh (1)' (3.7). +Details are given in the shell documentation csh(1) (3.7). .IP cat The .I cat -program concatenates a list of specified files on the +program concatenates a list of specified files on the .I "standard output" . It is usually used to look at the contents of a single file on the terminal, to `cat a file' (1.8, 2.3). .IP cd The .I cd -command is used to change the +command is used to change the .I "working directory" . With no arguments, .I cd -changes your -.I "working directory" +changes your +.I "working directory" to be your .I home directory (2.4, 2.7). @@ -259,15 +259,15 @@ is usually used because it is easier to type. The .I chsh command is used to change the shell which you use on \s-2UNIX\s0. -By default, you use an different version of the shell +By default, you use a different version of the shell which resides in `/bin/sh'. You can change your shell to `/bin/csh' by doing .DS -chsh your-login-name /bin/csh +chsh -s /bin/csh your-login-name .DE Thus I would do .DS -chsh bill /bin/csh +chsh -s /bin/csh bill .DE It is only necessary to do this once. The next time you log in to \s-2UNIX\s0 after doing this command, @@ -280,10 +280,10 @@ is a program which compares files. It is usually used on binary files, or to see if two files are identical (3.6). For comparing text files the program .I diff , -described in `diff (1)' is used. +described in diff(1) is used. .IP command A function performed by the system, either by the shell -(a builtin +(a builtin .I command ) or by a program residing in a file in a directory within the \s-2UNIX\s0 system, is called a @@ -300,7 +300,7 @@ command names the function to be performed (1.1). .IP "command substitution" .br The replacement of a command enclosed in `\`' characters -by the text output by that command +by the text output by that command is called .I "command substitution" (4.3). @@ -309,7 +309,7 @@ A part of a .I pathname between `/' characters is called a .I component -of that +of that .I pathname . A variable which has multiple strings as value is said to have @@ -344,17 +344,17 @@ character (e.g. `^C' for .IP "core\ dump" When a program terminates abnormally, the system places an image of its current state in a file named `core'. -This +This .I "core dump" -can be examined with the system debugger `adb (1)' -or `sdb (1)' in order to determine what went wrong with the program (1.8). +can be examined with the system debugger gdb(1) +in order to determine what went wrong with the program (1.8). If the shell produces a message of the form .DS -Illegal instruction (core dumped) +Segmentation fault (core dumped) .DE -(where `Illegal instruction' is only one of several possible +(where `Segmentation fault' is only one of several possible messages), you should report this to the author of the program -or a system administrator, +or a system administrator, saving the `core' file. .IP cp The @@ -394,15 +394,15 @@ command prints the current date and time (1.3). .I Debugging is the process of correcting mistakes in programs and shell scripts. The shell has several options and variables which may be used -to aid in shell -.I debugging +to aid in shell +.I debugging (4.4). .IP default: The label .I default: is used within shell .I switch -statements, as it is in the C language +statements, as it is in the C language, to label the code to be executed if none of the .I case labels matches the value switched on (3.7). @@ -412,40 +412,40 @@ The or \s-2RUBOUT\s0 key on the terminal normally causes an interrupt to be sent to the current job. -Many users change the interrupt character to be ^C. +Most users map the interrupt character to ^C. .IP detached -A command that continues running in the -.I background -after you logout is said to be +A command that continues running in the +.I background +after you log out is said to be .I detached . .IP diagnostic An error message produced by a program is often referred to as a .I diagnostic . -Most error messages are not written to the +Most error messages are not written to the .I "standard output" , since that is often directed away from the terminal (1.3, 1.5). Error messages are instead written to the .I "diagnostic output" which may be directed away from the terminal, but usually is not. -Thus -.I diagnostics +Thus +.I diagnostics will usually appear on the terminal (2.5). .IP directory A structure which contains files. -At any time you are in one particular -.I directory -whose names can be printed by the command +At any time you are in one particular +.I directory +whose name can be printed by the command .I pwd . The .I chdir -command will change you to another -.I directory , +command will change you to another +.I directory , and make the files -in that -.I directory -visible. The -.I directory -in which you are when you first login is your +in that +.I directory +visible. The +.I directory +in which you are when you first log in is your .I home directory (1.1, 2.7). .IP "directory\ stack" @@ -468,12 +468,12 @@ as the first directory name on the left (2.7). The .I dirs command prints the shell's -.I "directory stack" +.I "directory stack" (2.7). .IP du The .I du -command is a program (described in `du (1)') which +command is a program (described in du(1)) which prints the number of disk blocks is all directories below and including your current .I "working directory" @@ -509,13 +509,13 @@ and whenever a command reads to the end of a file which it has been given as input. Commands receiving input from a .I pipe -receive an -.I "end\f1-\fPof\f1-\fPfile" +receive an +.I "end\f1-\fPof\f1-\fPfile" when the command sending them input completes. -Most commands terminate when they receive an +Most commands terminate when they receive an .I "end\f1-\fPof\f1-\fPfile" . -The shell has an option to ignore -.I "end\f1-\fPof\f1-\fPfile" +The shell has an option to ignore +.I "end\f1-\fPof\f1-\fPfile" from a terminal input which may help you keep from logging out accidentally by typing too many control-d's (1.1, 1.8, 3.8). @@ -537,15 +537,15 @@ In this example, \e .I escape s `*' (1.7). There is also a non-printing character called -.I escape , +.I escape , usually labelled \s-2ESC\s0 or \s-2ALTMODE\s0 on terminal keyboards. Some older \s-2UNIX\s0 systems use this character to indicate that -output is to be -.I suspended . +output is to be +.I suspended . Most systems use control-s to stop the output and control-q to start it. .IP /etc/passwd This file contains information about the accounts currently on the @@ -561,7 +561,7 @@ The commands and .I grep are often used to search for information in this file. -See `finger (1)', `passwd(5)', and `grep (1)' for more details. +See finger(1), passwd(5), and grep(1) for more details. .IP exit The .I exit @@ -577,7 +577,7 @@ a status of zero being considered The .I exit command can be used to force a shell command script to give a non-zero -.I "exit status" +.I "exit status" (3.6). .IP expansion The replacement of strings in the shell input which contain metacharacters @@ -587,17 +587,17 @@ Thus the replacement of the word `*' by a sorted list of files in the current directory is a `filename expansion'. Similarly the replacement of the characters `!!' by the text of the last command is a `history expansion'. -.I Expansions +.I Expansions are also referred to as .I substitutions (1.6, 3.4, 4.2). .IP expressions -.I Expressions +.I Expressions are used in the shell to control the conditional structures used in the writing of shell scripts and in calculating values for these scripts. -The operators available in shell -.I expressions +The operators available in shell +.I expressions are those of the language C (3.5). .IP extension @@ -606,8 +606,8 @@ Filenames often consist of a name and an .I extension separated by the character `.'. -By convention, groups of related files often share the same -.I root +By convention, groups of related files often share the same +.I root name. Thus if `prog.c' were a C program, then the object file for this program would be stored in `prog.o'. @@ -634,28 +634,28 @@ job in the Each file in \s-2UNIX\s0 has a name consisting of up to 14 characters and not including the character `/' which is used in .I pathname -building. Most +building. Most .I filenames -do not begin with the character `.', and contain +do not begin with the character `.', and contain only letters and digits with perhaps a `.' separating the .I base -portion of the -.I filename -from an -.I extension +portion of the +.I filename +from an +.I extension (1.6). .IP "filename expansion" .br -.I "Filename expansion" +.I "Filename expansion" uses the metacharacters `*', `?' and `[' and `]' to provide a convenient mechanism for naming files. -Using -.I "filename expansion" +Using +.I "filename expansion" it is easy to name all the files in -the current directory, or all files which have a common -.I root -name. Other -.I "filename expansion" +the current directory, or all files which have a common +.I root +name. Other +.I "filename expansion" mechanisms use the metacharacter `~' and allow files in other users' directories to be named easily (1.6, 4.2). .IP flag @@ -685,7 +685,7 @@ shell is waiting for them to finish before prompting for another command they are said to be .I "foreground jobs" or -.I "running in the foreground" \&. +.I "running in the foreground" \&. This is as opposed to .I background . .I Foreground @@ -709,14 +709,14 @@ will print each line in the file which contains the string `bill'. Actually, .I grep -scans for +scans for .I "regular expressions" in the sense of the editors -`ed (1)' and `ex (1)'. +ed(1) and ex(1). .I Grep stands for -`globally find -.I "regular expression" +`globally find +.I "regular expression" and print' (2.4). .IP head The @@ -740,8 +740,8 @@ is the part after the last `/'. The `:h' and `:t' modifiers allow the .I head or .I tail -of a -.I pathname +of a +.I pathname stored in a shell variable to be used (3.6). .IP history The @@ -756,12 +756,12 @@ where these commands are kept, and a variable which controls how large this list is (2.3). .IP "home\ directory" .br -Each user has a +Each user has a .I "home directory" , which is given in your entry in the password file, .I /etc/passwd . -This is the directory which you are placed in when you first login. +This is the directory which you are placed in when you first log in. The .I cd or @@ -769,11 +769,11 @@ or command with no arguments takes you back to this directory, whose name is recorded in the shell variable .I home . -You can also access the -.I "home directories" +You can also access the +.I "home directories" of other users in forming -filenames using a -.I "filename expansion" +filenames using a +.I "filename expansion" notation and the character `~' (1.6). .IP if A conditional command within the shell, the @@ -793,7 +793,7 @@ variable if you wish in your .I \&.login file and then use the command .I logout -to logout. +to log out. This is useful if you sometimes accidentally type too many control-d characters, logging yourself off (2.2). @@ -802,26 +802,26 @@ Many commands on \s-2UNIX\s0 take information from the terminal or from files which they then act on. This information is called .I input . -Commands normally read for -.I input +Commands normally read +.I input from their .I "standard input" which is, by default, the terminal. -This -.I "standard input" +This +.I "standard input" can be redirected from a file using a shell metanotation with the character `<'. -Many commands will also read from a file specified as argument. -Commands placed in +Many commands will also read from a file specified as an argument. +Commands placed in .I pipelines will read from the output of the previous -command in the +command in the .I pipeline . -The leftmost command in a -.I pipeline +The leftmost command in a +.I pipeline reads from the terminal if -you neither redirect its -.I input +you neither redirect its +.I input nor give it a filename to use as .I "standard input" . Special mechanisms exist for supplying input to commands in shell @@ -833,18 +833,18 @@ is a signal to a program that is generated by typing ^C. (On older versions of UNIX the \s-2RUBOUT\s0 or \s-2DELETE\s0 key were used for this purpose.) It causes most programs to stop execution. Certain programs, such as the shell and the editors, -handle an -.I interrupt +handle an +.I interrupt in special ways, usually by stopping what they are doing and prompting for another command. While the shell is executing another command and waiting for it -to finish, the shell does not listen to -.I interrupts. -The shell often wakes up when you hit -.I interrupt +to finish, the shell does not listen to +.I interrupts . +The shell often wakes up when you hit +.I interrupt because many commands -die when they receive an -.I interrupt +die when they receive an +.I interrupt (1.8, 3.9). .IP job One or more commands @@ -852,8 +852,8 @@ typed on the same input line separated by `|' or `;' characters are run together and are called a .I job \&. Simple commands run by themselves without any `|' or `;' characters -are the simplest -.I jobs. +are the simplest +.I jobs . .I Jobs are classified as .I foreground , @@ -866,7 +866,11 @@ The builtin functions that control the execution of jobs are called .I "job control" commands. These are -.I "bg, fg, stop, kill" +.I bg , +.I fg , +.I stop , +and +.I kill (2.6). .IP "job\ number" When each job @@ -897,14 +901,14 @@ The file .I \&.login in your .I home -directory is read by the shell each time you login to \s-2UNIX\s0 +directory is read by the shell each time you log in to \s-2UNIX\s0 and the commands there are executed. There are a number of commands which are usefully placed here, especially .I set commands to the shell itself (2.1). .IP "login\ shell" -The shell that is started on your terminal when you login is called +The shell that is started on your terminal when you log in is called your .I "login shell" . It is different from other shells which you may run (e.g. on @@ -913,18 +917,18 @@ in that it reads the .I \&.login file before reading commands from the terminal and it reads the .I \&.logout -file after you logout +file after you log out (2.1). .IP logout The .I logout command causes a login shell to exit. Normally, a login shell will exit when you hit control-d -generating an -.I end\f1-\fPof\f1-\fPfile, +generating an +.I end\f1-\fPof\f1-\fPfile , but if you have set .I ignoreeof -in you +in your .I \&.login file then this will not work and you must use .I logout @@ -972,7 +976,7 @@ users (1.1, 2.1), whether they are logged on or not. The .I make command is used to maintain one or more related files and to -organize functions to be performed on these files. +organize functions to be performed on these files. In many ways .I make is easier to use, and more helpful than @@ -981,23 +985,24 @@ shell command scripts (3.2). The file containing commands for .I make is called -.I makefile -or +.I makefile +or .I Makefile (3.2). .IP manual -The -.I manual +The +.I manual often referred to is the `\s-2UNIX\s0 manual'. -It contains 8 numbered sections with a description of each \s-2UNIX\s0 +It contains 9 numbered sections with a description of each \s-2UNIX\s0 program (section 1), system call (section 2), subroutine (section 3), device (section 4), special data structure (section 5), game (section 6), -miscellaneous item (section 7) and system administration program (section 8). +miscellaneous item (section 7), system administration program (section 8), +and kernel internals (section 9). There are also supplementary documents (tutorials and reference guides) for individual programs which require explanation in more detail. -An online version of the -.I manual +An online version of the +.I manual is accessible through the .I man command. @@ -1005,8 +1010,7 @@ Its documentation can be obtained online via .DS man man .DE -If you can't decide what manual page to look in, try the -.I apropos (1) +If you can't decide what manual page to look in, try the apropos(1) command. The supplementary documents are in subdirectories of /usr/doc. .IP metacharacter @@ -1018,17 +1022,17 @@ These characters are called If it is necessary to place these characters in arguments to commands without them having their special meaning then they must be .I quoted . -An example of a -.I metacharacter -is the character `>' which is used +An example of a +.I metacharacter +is the character `>', which is used to indicate placement of output into a file. For the purposes of the .I history mechanism, -most unquoted +most unquoted .I metacharacters form separate words (1.4). -The appendix to this user's manual lists the +The appendix to this user's manual lists the .I metacharacters in groups by their function. .IP mkdir @@ -1036,13 +1040,13 @@ The .I mkdir command is used to create a new directory. .IP modifier -Substitutions with the -.I history +Substitutions with the +.I history mechanism, keyed by the character `!' or of variables using the metacharacter `$', are often subjected to modifications, indicated by placing the character `:' after the -substitution and following this with the -.I modifier +substitution and following this with the +.I modifier itself. The .I "command substitution" @@ -1081,55 +1085,55 @@ The .I notify variable, if set, causes the shell to always report the termination of -.I background +.I background jobs exactly when they occur (2.6). .IP onintr The .I onintr command is built into the shell and is used to control the action -of a shell command script when an -.I interrupt +of a shell command script when an +.I interrupt signal is received (3.9). .IP output Many commands in \s-2UNIX\s0 result in some lines of text which are called their -.I output. -This -.I output +.I output . +This +.I output is usually placed on what is known as the -.I "standard output" +.I "standard output" , which is normally connected to the user's terminal. The shell has a syntax using the metacharacter `>' for redirecting -the -.I "standard output" +the +.I "standard output" of a command to a file (1.3). Using the .I pipe mechanism and the metacharacter `|' it is also possible for -the -.I "standard output" -of one command to become the -.I "standard input" +the +.I "standard output" +of one command to become the +.I "standard input" of another command (1.5). Certain commands such as the line printer daemon -.I p -do not place their results on the -.I "standard output" +.I lpd +do not place their results on the +.I "standard output" but rather in more useful places such as on the line printer (2.3). Similarly the .I write command places its output on another user's terminal rather than its -.I "standard output" +.I "standard output" (2.3). Commands also have a .I "diagnostic output" where they write their error messages. -Normally these go to the terminal even if the -.I "standard output" +Normally these go to the terminal even if the +.I "standard output" has been sent to a file or another command, but it is possible -to direct error diagnostics along with -.I "standard output" +to direct error diagnostics along with +.I "standard output" using a special metanotation (2.5). .IP path The shell has a variable @@ -1147,10 +1151,11 @@ Since the normal definition of the .I path variable is .DS -path (. /usr/ucb /bin /usr/bin) +path (/bin /usr/bin .) .DE -the shell normally looks in the current directory, and then in -the standard system directories `/usr/ucb', `/bin' and `/usr/bin' for the named +the shell normally looks in the standard system directories +`/bin' and `/usr/bin', +and then the current directory, for the named command (2.2). If the command cannot be found the shell will print an error diagnostic. Scripts of shell commands will be executed using another shell to interpret @@ -1160,43 +1165,43 @@ This is normally true because a command of the form chmod 755 script .DE was executed to turn this execute permission on (3.3). -If you add new commands to a directory in the -.I path , +If you add new commands to a directory in the +.I path , you should issue -the command -.I rehash +the command +.I rehash (2.2). .IP pathname A list of names, separated by `/' characters, forms a -.I pathname. +.I pathname . Each -.I component, +.I component , between successive `/' characters, names a directory -in which the next -.I component +in which the next +.I component file resides. -.I Pathnames +.I Pathnames which begin with the character `/' are interpreted relative to the .I root directory in the filesystem. -Other -.I pathnames +Other +.I pathnames are interpreted relative to the current directory as reported by -.I pwd. -The last component of a -.I pathname +.I pwd . +The last component of a +.I pathname may name a directory, but usually names a file. .IP pipeline -A group of commands which are connected together, the +A group of commands which are connected together, the .I "standard output" -of each connected to the -.I "standard input" +of each connected to the +.I "standard input" of the next, is called a -.I pipeline. +.I pipeline . The .I pipe mechanism used to connect these commands is indicated by @@ -1234,18 +1239,18 @@ command is used to print the current setting of variables in the environment (2.8). .IP process -An instance of a running program is called a -.I process +An instance of a running program is called a +.I process (2.6). -\s-2UNIX\s0 assigns each -.I process -a unique number when it is +\s-2UNIX\s0 assigns each +.I process +a unique number when it is started \- called the .I "process number" . -.I "Process numbers" -can be used to stop individual +.I "Process numbers" +can be used to stop individual .I processes -using the +using the .I kill or .I stop @@ -1259,21 +1264,21 @@ Usually synonymous with .I command ; a binary file or shell command script which performs a useful function is often -called a +called a .I program . .IP prompt -Many programs will print a -.I prompt +Many programs will print a +.I prompt on the terminal when they expect input. Thus the editor -`ex (1)' will print a `:' when it expects input. -The shell +ex(1) will print a `:' when it expects input. +The shell .I prompts for input with `% ' and occasionally with `? ' when reading commands from the terminal (1.1). The shell has a variable .I prompt -which may be set to a different value to change the shell's main +which may be set to a different value to change the shell's main .I prompt . This is mostly used when debugging the shell (2.8). .IP pushd @@ -1298,16 +1303,16 @@ stopped, awaiting some event (sleeping), and whether it is swapped out), and the amount of \s-2CPU\s0 time it has used so far. The command is identified by printing some of the words used when it was invoked (2.6). -Shells, such as the -.I csh -you use to run the -.I ps -command, are not normally shown in the output. +.\" Shells, such as the +.\" .I csh +.\" you use to run the +.\" .I ps +.\" command, are not normally shown in the output. .IP pwd The .I pwd -command prints the full -.I pathname +command prints the full +.I pathname of the current .I "working directory" \&. The @@ -1321,7 +1326,7 @@ is used to terminate programs which are behaving unreasonably. It normally produces a core image file (1.8). .IP quotation The process by which metacharacters are prevented their special -meaning, usually by using the character `\' in pairs, or by +meaning, usually by using the character `\'' in pairs, or by using the character `\e', is referred to as .I quotation (1.7). @@ -1346,7 +1351,7 @@ which does not begin with a `/' is called a .I "relative pathname" since it is interpreted .I relative -to the current +to the current .I "working directory" . The first .I component @@ -1377,18 +1382,18 @@ directories. The name used in .I pathnames to indicate the .I root -is `/'. -.I Pathnames +is `/'. +.I Pathnames starting with `/' are said to be .I absolute since they start at the .I root directory. .I Root -is also used as the part of a -.I pathname +is also used as the part of a +.I pathname that is left after removing -the +the .I extension . See .I filename @@ -1399,15 +1404,15 @@ key is often used to erase the previously typed character; some users prefer the \s-2BACKSPACE\s0 for this purpose. On older versions of \s-2UNIX\s0 this key served as the \s-2INTR\s0 character. .IP "scratch file" -Files whose names begin with a `#' are referred to as +Files whose names begin with a `#' are referred to as .I "scratch files" , since they are automatically removed by the system after a couple of days of non-use, or more frequently if disk space becomes tight (1.3). .IP script -Sequences of shell commands placed in a file are called shell command +Sequences of shell commands placed in a file are called shell command .I scripts . -It is often possible to perform simple tasks using these -.I scripts +It is often possible to perform simple tasks using these +.I scripts without writing a program in a language such as C, by using the shell to selectively run other programs (3.3, 3.10). .IP set @@ -1416,11 +1421,11 @@ The builtin command is used to assign new values to shell variables and to show the values of the current variables. Many shell variables have special meaning to the shell itself. -Thus by using the -.I set +Thus by using the +.I set command the behavior of the shell can be affected (2.1). .IP setenv -Variables in the environment `environ (5)' +Variables in the environment environ(5) can be changed by using the .I setenv builtin command (2.8). @@ -1428,19 +1433,19 @@ The .I printenv command can be used to print the value of the variables in the environment. .IP shell -A -.I shell +A +.I shell is a command language interpreter. -It is possible to write and run your own +It is possible to write and run your own .I shell , -as -.I shells +as +.I shells are no different than any other programs as far as the system is concerned. -This manual deals with the details of one particular +This manual deals with the details of one particular .I shell , called -.I csh. +.I csh . .IP "shell script" See .I script @@ -1462,8 +1467,8 @@ commands (1.8, 2.6). The .I sort program sorts a sequence of lines in ways that can be controlled -by argument -.I flags +by argument +.I flags (1.5). .IP source The @@ -1496,22 +1501,22 @@ when it finishes. By convention a .I status of zero indicates that the command succeeded. -Commands may return non-zero -.I status +Commands may return non-zero +.I status to indicate that some abnormal event has occurred. The shell variable .I status -is set to the -.I status +is set to the +.I status returned by the last command. It is most useful in shell command scripts (3.6). .IP stop The .I stop command causes a -.I background -job to become -.I suspended +.I background +job to become +.I suspended (2.6). .IP string A sequential group of characters taken together is called a @@ -1522,19 +1527,19 @@ can contain any printable characters (2.2). The .I stty program changes certain parameters inside \s-2UNIX\s0 which determine -how your terminal is handled. See `stty (1)' for a complete description (2.6). +how your terminal is handled. See stty(1) for a complete description (2.6). .IP substitution The shell implements a number of .I substitutions where sequences indicated by metacharacters are replaced by other sequences. -Notable examples of this are history -.I substitution +Notable examples of this are history +.I substitution keyed by the -metacharacter `!' and variable -.I substitution +metacharacter `!' and variable +.I substitution indicated by `$'. -We also refer to -.I substitutions +We also refer to +.I substitutions as .I expansions (3.4). @@ -1569,10 +1574,10 @@ statement in the language C (3.7). When a command which is being executed finishes we say it undergoes .I termination or -.I terminates. -Commands normally terminate when they read an +.I terminates . +Commands normally terminate when they read an .I end\f1-\fPof\f1-\fPfile -from their +from their .I "standard input" . It is also possible to terminate commands by sending them an @@ -1593,7 +1598,7 @@ The .I time command can be used to measure the amount of \s-2CPU\s0 and real time consumed by a specified command as well -as the amount of disk i/o, memory utilized, and number +as the amount of disk I/O, memory utilized, and number of page faults and swaps taken by the command (2.1, 2.8). .IP tset The @@ -1640,12 +1645,12 @@ and .I expansion (2.2, 3.4). .IP variables -.I Variables +.I Variables in .I csh hold one or more strings as value. -The most common use of -.I variables +The most common use of +.I variables is in controlling the behavior of the shell. See @@ -1654,7 +1659,7 @@ See and .I ignoreeof for examples. -.I Variables +.I Variables such as .I argv are also used in writing shell programs (shell command scripts) @@ -1668,7 +1673,7 @@ This is often useful in debugging shell scripts. The .I verbose variable is set by the shell's -.I \-v +.B \-v command line option (3.10). .IP wc The @@ -1684,37 +1689,37 @@ A sequence of characters which forms an argument to a command is called a .I word . Many characters which are neither letters, digits, `\-', `.' nor `/' -form -.I words +form +.I words all by themselves even if they are not surrounded by blanks. -Any sequence of characters may be made into a -.I word +Any sequence of characters may be made into a +.I word by surrounding it with `\'' characters except for the characters `\'' and `!' which require special treatment (1.1). -This process of placing special characters in -.I words +This process of placing special characters in +.I words without their special meaning is called .I quoting . .IP "working directory" .br At any given time you are in one particular directory, called -your +your .I "working directory" . This directory's name is printed by the .I pwd command and the files listed by .I ls are the ones in this directory. -You can change -.I "working directories" +You can change +.I "working directories" using .I chdir . .IP write The .I write command is an obsolete way of communicating with other users who are logged in to -\s-2UNIX\s0 (you have to take turns typing). If you are both using display -terminals, use \fItalk\fP(1), which is much more pleasant. +\s-2UNIX\s0 (you have to take turns typing). If you are both using display +terminals, use talk(1), which is much more pleasant. |