
Head (Unix)

head is a program on Unix and Unix-like operating systems used to display the beginning of a text file or piped data.
Syntax.
The command syntax is:
 head [options] <file_name>
By default, codice_1 will print the first 10 lines of its input to the standard output. 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 allow omitting codice_2 and instead directly specifying the number: codice_3. GNU head allows negative arguments for the codice_4 option, meaning to print all but the last - argument value counted - lines of each input file.
Flags.
 -c <x number of bytes> Copy first x number of bytes.
Other.
Many early versions of Unix did not have this command, and documentation and books used sed instead:
 sed 5q "filename"
The example prints every line (implicit) and quit after the fifth.
Implementations.
A codice_1 command is also part of ASCII's "MSX-DOS2 Tools" for MSX-DOS version 2. The command has also been ported to the IBM i operating system.