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 @(#)cat.1 8.3 (Berkeley) 5/2/95

.Dd June 15, 2014
.Dt CAT 1
.Os
.Sh NAME
.Nm cat
.Nd concatenate and print files
.Sh SYNOPSIS
.Nm
.Op Fl beflnstuv
.Op Fl B Ar bsize
.Op Fl
.Op 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,
and may appear multiple times in the
.Ar file
list.
If no
.Ar file
operands are given, standard input is read.

p
The word
.Dq concatenate
is just a verbose synonym for
.Dq catenate .

p
The options are as follows:
l -tag -width Ds t Fl B Ar bsize Read with a buffer size of
.Ar bsize
bytes, instead of the default buffer size which is the blocksize of the
output file.
t Fl b Implies the
.Fl n
option, but doesn't number blank lines.
t Fl e Implies the
.Fl v
option, and displays a dollar sign

q Ql $
at the end of each line
as well.
t Fl f Only attempt to display regular files.
t Fl l Set an exclusive advisory lock on the standard output file descriptor.
This lock is set using
.Xr fcntl 2
with the
.Dv F_SETLKW
command.
If the output file is already locked,
.Nm
will block until the lock is acquired.
t Fl n Number the output lines, starting at 1.
t Fl s Squeeze multiple adjacent empty lines, causing the output to be
single spaced.
t Fl t Implies the
.Fl v
option, and displays tab characters as
.Ql ^I
as well.
t Fl u The
.Fl u
option guarantees that the output is unbuffered.
t Fl v Displays non-printing characters so they are visible.
Control characters print as
.Ql ^X
for control-X; the delete
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.
.El
.Sh EXIT STATUS
.Ex -std cat
.Sh EXAMPLES
The command:
d -literal -offset indent c cat file1 .Ed

p
will print the contents of
.Ar file1
to the standard output.

p
The command:
d -literal -offset indent c cat file1 file2 > file3 .Ed

p
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 (e.g.,
.Xr sh 1 )
for more information on redirection.

p
The command:
d -literal -offset indent c cat file1 - file2 - file3 .Ed

p
will print the contents of
.Ar file1 ,
print data it receives from the standard input until it receives an
.Dv EOF

q 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 hexdump 1 ,
.Xr lpr 1 ,
.Xr more 1 ,
.Xr pr 1 ,
.Xr tac 1 ,
.Xr tail 1 ,
.Xr view 1 ,
.Xr vis 1 ,
.Xr fcntl 2
.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 expected to conform to the
.St -p1003.2-92
specification.

p
The flags
.Op Fl Bbeflnstv
are extensions to the specification.
.Sh HISTORY
A
.Nm
utility appeared in
.At v1 .
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
.Dq Li cat file1 file2 > file1
will cause the original data in file1 to be destroyed!
This is performed by the shell before
.Nm
is run.