man/man1/head.1

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 HEAD 1 "Nov 2, 2007"
 NAME
head - display first few lines of files
 SYNOPSIS
 "/usr/bin/head"

/usr/bin/head [-number | -n number] [filename]...


 "ksh93"

head [-qv] [-n lines] [-c chars] [-s skip][filename]...


 DESCRIPTION
 "/usr/bin/head"

The head utility copies the first number of lines of each
filename to the standard output. If no filename is given,
head copies lines from the standard input. The default value of
number is 10 lines.

When more than one file is specified, the start of each file looks like:
==> filename <==


Thus, a common way to display a set of short files, identifying each one, is:
example% head -9999 filename1 filename2 ...


 "ksh93"

The head built-in in ksh93 is associated with the /bin and
/usr/bin paths. It is invoked when head is executed without a
pathname prefix and the pathname search finds a /bin/head or
/usr/bin/head executable.

head copies one or more input files to standard output, stopping at a
designated point for each file or to the end of the file whichever comes first.
Copying ends at the point indicated by the options. By default, a header of the
form ==> filename <== is output before all but the first file but this
can be changed with the -q and -v options. If no file is given, or
if the file is -, head copies from standard input starting at the
current location.

The option argument for -c and -s can optionally be followed by one
of the following characters to specify a different unit other than a single
byte:
b

512 bytes


k

1-kilobyte


m

1-megabyte


For backwards compatibility, -number is equivalent to -n number.
 OPTIONS
 "/usr/bin/head"

The following options are supported by /usr/bin/head:
-n number

The first number lines of each input file is copied to standard output.
The number option-argument must be a positive decimal integer.


-number

The number argument is a positive decimal integer with the same effect as
the -n number option.


If no options are specified, head acts as if -n 10 had been
specified.
 "ksh93"

The following options are supported by the head built-in command in
ksh93:
-n

--lines=lines

Copy lines from each file. The default value is 10.


-c

--bytes=chars

Copy chars bytes from each file.


-q

--quiet|silent

Never output filename headers.


-s

--skip=skip

Skip skip characters or lines from each file before copying.


-v

--verbose

Always output filename headers.


 OPERANDS

The following operand is supported:
filename

A path name of an input file. If no file operands are specified, the
standard input is used.


 USAGE

See largefile(5) for the description of the behavior of head when
encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).
 EXAMPLES

Example 1 Writing the First Ten Lines of All Files

The following example writes the first ten lines of all files, except those
with a leading period, in the directory:

example% head *


 ENVIRONMENT VARIABLES

See environ(5) for descriptions of the following environment variables
that affect the execution of head: LANG, LC_ALL,
LC_CTYPE, LC_MESSAGES, and NLSPATH.
 EXIT STATUS

The following exit values are returned:
0

Successful completion.


>0

An error occurred.


 ATTRIBUTES

See attributes(5) for descriptions of the following attributes:
 "/usr/bin/head"


ATTRIBUTE TYPE ATTRIBUTE VALUE
CSI Enabled
Interface Stability Committed
Standard See standards(5).


 "ksh93"


ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability See below.


The ksh93 built-in binding to /bin and /usr/bin is Volatile.
The built-in interfaces are Uncommitted.
 SEE ALSO

cat(1), ksh93(1), more(1), pg(1), tail(1),
attributes(5), environ(5), largefile(5), standards(5)