The `AWKPATH' Environment Variable
==================================

   The previous section described how `awk' program files can be named
on the command line with the `-f' option.  In some `awk'
implementations, you must supply a precise path name for each program
file, unless the file is in the current directory.

   But in `gawk', if the file name supplied in the `-f' option does not
contain a `/', then `gawk' searches a list of directories (called the
"search path"), one by one, looking for a file with the specified name.

   The search path is actually a string consisting of directory names
separated by colons.  `gawk' gets its search path from the `AWKPATH'
environment variable.  If that variable does not exist, `gawk' uses the
default path, which is `.:/usr/lib/awk:/usr/local/lib/awk'.  (Programs
written by system administrators should use an `AWKPATH' variable that
does not include the current directory, `.'.)

   The search path feature is particularly useful for building up
libraries of useful `awk' functions.  The library files can be placed
in a standard directory that is in the default path, and then specified
on the command line with a short file name.  Otherwise, the full file
name would have to be typed for each file.

   By combining the `--source' and `-f' options, your command line
`awk' programs can use facilities in `awk' library files.

   Path searching is not done if `gawk' is in compatibility mode.  This
is true for both `-W compat' and `-W posix'.  *Note Command Line
Options: Options.

   *Note:* if you want files in the current directory to be found, you
must include the current directory in the path, either by writing `.'
as an entry in the path, or by writing a null entry in the path.  (A
null entry is indicated by starting or ending the path with a colon, or
by placing two colons next to each other (`::').)  If the current
directory is not included in the path, then files cannot be found in
the current directory.  This path search mechanism is identical to the
shell's.