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. Thus
cat file
displays the file on the standard output, and
cat file1 file2 >file3
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 1024-byte blocks unless the standard output is a terminal, in which case it is line buffered.
The −b option ignores blank lines and precedes all other output with line numbers.
The −e option displays a dollar sign ($) at the end of each output line.
The −n option precedes all output lines (including blank lines) with line numbers.
The −s option squeezes adjacent empty lines so that the output is displayed single spaced.
The −t option displays 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.
The −u option makes the output completely unbuffered.
The −v option displays 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.
RESTRICTIONS
Beware of ‘cat a b >a’ and ‘cat a b >b’, which destroy the input files before reading them.