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Diffstat (limited to 'bin/cat/cat.1')
| -rw-r--r-- | bin/cat/cat.1 | 137 |
1 files changed, 99 insertions, 38 deletions
diff --git a/bin/cat/cat.1 b/bin/cat/cat.1 index 617182a710d..b6e6798efd1 100644 --- a/bin/cat/cat.1 +++ b/bin/cat/cat.1 @@ -1,4 +1,4 @@ -.\" $OpenBSD: cat.1,v 1.7 1998/12/15 01:20:16 aaron Exp $ +.\" $OpenBSD: cat.1,v 1.8 1999/03/03 00:54:43 aaron Exp $ .\" $NetBSD: cat.1,v 1.12 1995/09/27 05:38:55 cgd Exp $ .\" .\" Copyright (c) 1989, 1990, 1993 @@ -46,83 +46,132 @@ .Sh SYNOPSIS .Nm cat .Op Fl benstuv -.Op Fl -.Op Ar +.Op Ar file No | \&- Ar ... .Sh DESCRIPTION The .Nm utility reads files sequentially, writing them to the standard output. The .Ar file -operands are processed in command line order. -A single dash represents the standard input. +operands are processed in command-line order. +If +.Ar file +is a single dash +.Pq Sq \&- +or absent, +.Nm +reads from the standard input. .Pp The options are as follows: .Bl -tag -width Ds +.It Fl n +Number the output lines, starting at 1. .It Fl b Implies the .Fl n option but doesn't number blank lines. +.It Fl v +Displays non-printing characters so they are visible. +Control characters print as +.Ql ^X +for control-X. The only exception is the tab character, control-I (see the +.Fl t +option). The DEL +character (octal 0177) prints as +.Ql ^? . +Non-ASCII characters (with the high bit set) are printed as +.Ql M- +(for meta) followed by the character for the low 7 bits. .It Fl e Implies the .Fl v -option, and displays a dollar sign +option and also prints a dollar sign .Pq Ql \&$ -at the end of each line -as well. -.It Fl n -Number the output lines, starting at 1. -.It Fl s -Squeeze multiple adjacent empty lines, causing the output to be -single spaced. +at the end of each line. .It Fl t Implies the .Fl v -option, and displays tab characters as -.Ql ^I -as well. +option and also prints tab characters as +.Ql ^I . +.It Fl s +Squeeze multiple adjacent empty lines, causing the output to be +single spaced. .It Fl u The .Fl u -option guarantees that the output is unbuffered. -.It Fl v -Displays non-printing characters so they are visible. -Control characters print as -.Ql ^X -for control-X. The DEL -character (octal 0177) prints as -.Ql ^? . -Non-ASCII characters (with the high bit set) are printed as -.Ql M- -(for meta) followed by the character for the low 7 bits. +option guarantees that the output is unbuffered (see +.Xr setbuf 3 ) . .El .Pp The .Nm utility exits 0 on success or >0 if an error occurred. -.Sh BUGS -Because of the shell language mechanism used to perform output -redirection, the command -.Dq Li cat file1 file2 > file1 -will cause the original data in +.Sh EXAMPLES +The command: +.Bd -literal -offset indent +.Ic cat file1 +.Ed +.Pp +will print the contents of .Ar file1 -to be destroyed! +to the standard output. +.Pp +The command: +.Bd -literal -offset indent +.Ic cat file1 file2 > file3 +.Ed +.Pp +will sequentially print the contents of +.Ar file1 +and +.Ar file2 +to the file +.Ar file3 , +truncating +.Ar file3 +if it already exists. See the manual page for your shell +.Po +i.e., +.Xr sh 1 +.Pc +for more information on redirection. +.Pp +The command: +.Bd -literal -offset indent +.Ic cat file1 - file2 - file3 +.Ed +.Pp +will print the contents of +.Ar file1 , +print data it receives from the standard input until it receives an +.Dv EOF +(^D) character, print the contents of +.Ar file2 , +read and output contents of the standard input again, then finally output +the contents of +.Ar file3 . +Note that if the standard input referred to a file, the second dash +on the command-line would have no effect, since the entire contents of the file +would have already been read and printed by +.Nm cat +when it encountered the first +.Dq \&- +operand. .Sh SEE ALSO .Xr head 1 , +.Xr less 1 , .Xr more 1 , .Xr pr 1 , +.Xr sh 1 , .Xr tail 1 , -.Xr vis 1 +.Xr vis 1 , +.Xr setbuf 3 .Rs .%A Rob Pike .%T "UNIX Style, or cat -v Considered Harmful" .%J "USENIX Summer Conference Proceedings" .%D 1983 .Re -.Sh HISTORY -A -.Nm -utility appeared in Version 6 AT&T UNIX. .Sh STANDARDS The .Nm @@ -133,3 +182,15 @@ specification. The flags .Op Fl benstv are extensions to the specification. +.Sh HISTORY +A +.Nm +utility appeared in Version 6 AT&T UNIX. +.Sh BUGS +Because of the shell language mechanism used to perform output +redirection, the command +.Ic cat file1 file2 > file1 +will cause the original data in +.Ar file1 +to be destroyed! + |