cat(1)
NAME
cat − concatenate and print
SYNTAX
cat [ −b ] [ −e ] [ −n ] [ −s ] [ −t ] [ −u ] [ −v ] file...
DESCRIPTION
The cat command reads each file in sequence and displays it on the standard output. For example:
cat file
The first command displays the file on the standard output, and
cat file1 file2 >file3
The second command concatenates the first two files and places the result on the third.
If no input file is given, or if the argument “−” is encountered, cat reads from the standard input file. Output is buffered in 512-byte blocks unless the standard output is a terminal, in which case it is line buffered.
OPTIONS
−bIgnores blank lines and precedes all other output with line numbers.
−eDisplays a dollar sign ($) at the end of each output line.
−nPrecedes all output lines (including blank lines) with line numbers.
−sSqueezes adjacent empty lines so that the output is displayed single spaced.
−tDisplays all non-printing characters including tabs in the output. In addition to those representations used with the −v option, all tab characters are displayed as ^I.
−uMakes the output completely unbuffered.
−vDisplays non-printing characters (except tabs). <CTRLx> (control character x) prints as ^X. The delete character (octal 0177) prints as ^?. Non-ascii characters (with the high bit set) are printed as M- (for meta) followed by the character of the low 7 bits.
cat a b >a
cat a b >b
These commands destroy the input files before reading them.