NAME

cat − catenate and print

SYNOPSIS

cat [ −u ] [ −n ] [ −s ] [ −v ] file ... 

DESCRIPTION

Cat reads each file in sequence and writes it on the standard output.  Thus

cat file

prints the file, 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 −u option causes the output to be completely unbuffered. 

The option −n causes the output lines to be numbered sequentially from 1.  Giving −b with −n causes numbers to be omitted from blank lines. 

The option −s causes the output to be single spaced by crushing out multiple adjacent empty lines. 

The option −v causes non-printing characters to be printed in a visible way.  Control characters print like ^X for control-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.  A −e option may be given with −v and causes the ends of lines to be followed by the character ‘$’; the −t option with −v causes tabs to be printed as ^I. 

SEE ALSO

cp(1), ex(1), more(1), pr(1), tail(1)

BUGS

Beware of ‘cat a b >a’ and ‘cat a b >b’, which destroy the input files before reading them.