By default, head will print the first 10 lines of its input to the standard output.
Option flags
-n⟨count⟩
--lines=⟨count⟩
The number of lines printed may be changed with a command line option. The following example shows the first 20 lines of filename:
head -n 20 filename
This displays the first 5 lines of all files starting with foo:
head -n 5 foo*
Most versions[citation needed] allow omitting n and instead directly specifying the number: -5. GNU head allows negative arguments for the -n option, meaning to print all but the last - argument value counted - lines of each input file.
-c⟨bytes⟩
--bytes=⟨bytes⟩
Print first x number of bytes.
Other command
Many early versions of Unix and Plan 9 did not have this command, and documentation and books used sed instead:
sed 5q filename
The example prints every line (implicit) and quits after the fifth.
Equivalently, awk may be used to print the first five lines in a file:
awk 'NR < 6' filename
However, neither sed nor awk were available in early versions of BSD, which were based on
Version 6 Unix, and included head.[1]
Implementations
A head command is also part of ASCII's MSX-DOS2 Tools for MSX-DOS version 2.[2] The head command has also been ported to the IBM i operating system.[3]
