diff options
Diffstat (limited to 'bin')
| -rw-r--r-- | bin/cat/cat.1 | 94 | ||||
| -rw-r--r-- | bin/cat/cat.c | 4 |
2 files changed, 84 insertions, 14 deletions
diff --git a/bin/cat/cat.1 b/bin/cat/cat.1 index a762fb1..740734a 100644 --- a/bin/cat/cat.1 +++ b/bin/cat/cat.1 @@ -37,14 +37,13 @@ .\" .Dd May 2, 1995 .Dt CAT 1 -.Os BSD 3 +.Os .Sh NAME .Nm cat .Nd concatenate and print files .Sh SYNOPSIS .Nm cat .Op Fl benstuv -.Op Fl .Op Ar .Sh DESCRIPTION The @@ -52,8 +51,14 @@ The 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 indent @@ -94,29 +99,94 @@ characters (with the high bit set) are printed as .Sh DIAGNOSTICS The .Nm -utility exits 0 on success, and >0 if an error occurs. -.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 file1 to be destroyed! +utility exits 0 on success or >0 if an error occurred. +.Sh EXAMPLES +The command: +.Bd -literal -offset indent +.Ic cat file1 +.Ed +.Pp +will print the contents of +.Ar file1 +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 (i.e., +.Xr sh 1 ) +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 +.Pq Sq ^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 +when it encountered the first +.Ql \&- +operand. .Sh SEE ALSO .Xr head 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 STANDARDS +The +.Nm +utility is compliant with the +.St -p1003.2-92 +specification. +.Pp +The flags +.Op Fl benstv +are extensions to the specification. .Sh HISTORY A .Nm -command appeared in Version 1 AT&T UNIX. +utility appeared in +.At v1 . .An Dennis Ritchie designed and wrote the first man page. It appears to have been .Xr cat 1 . +.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! diff --git a/bin/cat/cat.c b/bin/cat/cat.c index f88c125..c2f11dd 100644 --- a/bin/cat/cat.c +++ b/bin/cat/cat.c @@ -96,7 +96,7 @@ main(argc, argv) tflag = vflag = 1; /* -t implies -v */ break; case 'u': - setbuf(stdout, (char *)NULL); + setbuf(stdout, NULL); break; case 'v': vflag = 1; @@ -249,7 +249,7 @@ raw_cat(rfd) err(1, "%s", filename); bsize = MAX(sbuf.st_blksize, 1024); if ((buf = malloc(bsize)) == NULL) - err(1, NULL); + err(1, "buffer"); } while ((nr = read(rfd, buf, bsize)) > 0) for (off = 0; nr; nr -= nw, off += nw) |
