The cat(1) utility reads files sequentially, writing them to
the standard output. The file operands are processed in
command-line order. A single dash represents the standard input.
The options are as follows:
-b
Like -n but does not number blank lines.
-e
Like -v and displays a dollar sign ($) at the end of
each line.
-n
Number the output lines beginning at 1.
-s
Do not display any error messages for unreadable or
non-existant files.
-S
Remove blank lines adjacent to another empty line, causing a
single blank line to be output.
-t
Like -v and also displays tab characters as ^I.
-u
The -u option ensures that the output is
unbuffered.
-v
Displays non-printing characters so they are visible. Control
characters print as ^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 defined by
the lower seven bits.
Because of the shell language mechanism that is used to perform
output redirection, the following command will cause the original
data in file1 to be destroyed unless the shell is set for
noclobber.