File: coreutils.info, Node: head invocation, Next: tail invocation, Up: Output of parts of files
5.1 'head': Output the first part of files
==========================================
'head' prints the first part (10 lines by default) of each FILE; it
reads from standard input if no files are given or when given a FILE of
'-'. Synopsis:
head [OPTION]... [FILE]...
If more than one FILE is specified, 'head' prints a one-line header
consisting of:
==> FILE NAME <==
before the output for each FILE.
The program accepts the following options. Also see *note Common
options::.
'-c [-]NUM'
'--bytes=[-]NUM'
Print the first NUM bytes, instead of initial lines. However, if
NUM is prefixed with a '-', print all but the last NUM bytes of
each file. NUM may be, or may be an integer optionally followed
by, one of the following multiplicative suffixes:
'b' => 512 ("blocks")
'KB' => 1000 (KiloBytes)
'K' => 1024 (KibiBytes)
'MB' => 1000*1000 (MegaBytes)
'M' => 1024*1024 (MebiBytes)
'GB' => 1000*1000*1000 (GigaBytes)
'G' => 1024*1024*1024 (GibiBytes)
and so on for 'T', 'P', 'E', 'Z', and 'Y'.
'-n [-]NUM'
'--lines=[-]NUM'
Output the first NUM lines. However, if NUM is prefixed with a
'-', print all but the last NUM lines of each file. Size
multiplier suffixes are the same as with the '-c' option.
'-q'
'--quiet'
'--silent'
Never print file name headers.
'-v'
'--verbose'
Always print file name headers.
'-z'
'--zero-terminated'
Delimit items with a zero byte rather than a newline (ASCII LF).
I.e., treat input as items separated by ASCII NUL and terminate
output items with ASCII NUL. This option can be useful in
conjunction with 'perl -0' or 'find -print0' and 'xargs -0' which
do the same in order to reliably handle arbitrary file names (even
those containing blanks or other special characters).
For compatibility 'head' also supports an obsolete option syntax
'-[NUM][bkm][cqv]', which is recognized only if it is specified first.
NUM is a decimal number optionally followed by a size letter ('b', 'k',
'm') as in '-c', or 'l' to mean count by lines, or other option letters
('cqv'). Scripts intended for standard hosts should use '-c NUM' or '-n
NUM' instead. If your script must also run on hosts that support only
the obsolete syntax, it is usually simpler to avoid 'head', e.g., by
using 'sed 5q' instead of 'head -5'.
An exit status of zero indicates success, and a nonzero value
indicates failure.