cat(C)

cat -- concatenate and display files

Syntax

cat [ -u ] [ -s ] [ -v ] [ -t ] [ -e ] [ file ... ]

Description

cat reads each file in sequence and writes it on the standard output. If no input file is given, or if a single dash (-) is given, cat reads from the standard input. The options are:

-s: Suppresses warnings about nonexistent files.
-u: Causes the output to be unbuffered.
-v: Causes non-printing characters (with the exception of tabs, newlines, and form feeds) to be displayed. Control characters are displayed as ^X (<Ctrl>x), where X is the key pressed with the <Ctrl> key (for example, <Ctrl>m is displayed as ^M). The <Del> character (octal 0177) is printed as ^?. Non-ASCII characters (with the high bit set) are printed as M -x, where x is the character specified by the seven low order bits.
-t: Causes tabs to be printed as ^I and form feeds as ^L. This option is ignored if the -v option is not specified.
-e: Causes a ``$'' character to be printed at the end of each line (prior to the new-line). This option is ignored if the -v option is not set.

Exit values

cat returns the following values:

0: all input files were output successfully
>0: an error occurred

Examples

The following example displays file on the standard output:

cat file

The following example concatenates file1 and file2 and places the result in file3:

cat file1 file2 >file3

The following example concatenates file1 and appends it to file2:

cat file1 >> file2

Warning

Command lines such as:

cat file1 file2 > file1

will cause the original data in file1 to be lost; therefore, you must be careful when using special shell characters.

Standards conformance

cat is conformant with:

ISO/IEC DIS 99452:1992, Information technology Portable Operating System Interface (POSIX) Part 2: Shell and Utilities (IEEE Std 1003.21992);
AT&T SVID Issue 2;
X/Open CAE Specification, Commands and Utilities, Issue 4, 1992.