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/usr/bin/head [-q] [-v] [-number ] [ -n number ] [ -c number] [filename]...
head [-qv] [-n lines] [-c chars] [-s skip] [filename]...
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. If -c is specified, head copies the first number of bytes of each filename.
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 ...
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
1-kilobyte
1-megabyte
For backwards compatibility, -number is equivalent to -n number.
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.
The first number bytes of each input file is copied to standard output. The number option-argument must be a positive decimal integer. Note, output may end in the middle of a character if a file contains multi-byte characters.
The number argument is a positive decimal integer with the same effect as the -n number option.
head will not print a header in between each specified file.
head will always print a header in between each specified file.
If no options are specified, head acts as if -n 10 had been specified.
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.
--bytes=chars
Copy chars bytes from each file.
--quiet|silent
Never output filename headers.
--skip=skip
Skip skip characters or lines from each file before copying.
--verbose
Always output filename headers.
The following operand is supported: filename
A path name of an input file. If no file operands are specified, the standard input is used.
See largefile(5) for the description of the behavior of head when encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).
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 *
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.
The following exit values are returned: 0
Successful completion.
An error occurred.
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE ATTRIBUTE VALUE |
| CSI Enabled |
| Interface Stability Committed |
| Standard See standards(5). |
| 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.
cat(1), ksh93(1), more(1), pg(1), tail(1), attributes(5), environ(5), largefile(5), standards(5)