.TH READDIR 3am "June 02 2023" "Free Software Foundation" "GNU Awk Extension Modules"
.SH NAME
readdir \- directory input parser for gawk
.SH SYNOPSIS
.ft CW
@load "readdir"
.sp
BEGIN { PROCINFO["readdir_override"] = \fIany_value\fP }  # optional
.ft R
.SH DESCRIPTION
The
.I readdir
extension
adds an input parser for directories.
.PP
When this extension is in use, instead of skipping directories named
on the command line (or with
.BR getline ),
they are read, with each entry returned as a record.
.PP
The record consists of three fields
separated by forward slash characters.
The first two are the inode number and the
filename, and
the third field is a single letter indicating the type of the
file:
.B f
for file,
.B d
for directory,
.B b
for a block device,
.B c
for a character device,
.B p
for a FIFO,
.B l
for a symbolic link, or
.B s
for a socket.
.PP
On systems where the directory entry contains the file type, the third
field is filled in from that information.
On systems without the file type information, the extension falls back
to calling
.IR stat (2),
in order to provide the information.
Thus the third field should never be
.BR u " (unknown)."
.PP
Normally, when reading directories, you should set
.B FS
equal to \fB"/"\fP.  However, you may instead chose to create
\fBPROCINFO["readdir_override"]\fP (with any value). If this element
exists when the directory is opened, then the extension automatically
sets the fields in each record for you.
.PP
By default, if a directory cannot be opened (due to permission problems,
for example),
.I gawk
will exit.
As with regular files, this situation can be handled using a
.B BEGINFILE
rule that checks
.B ERRNO
and prints an error or otherwise handles the problem.
.\" .SH BUGS
.SH EXAMPLE
.ft CW
.nf
@load "readdir"
\&...
BEGIN { FS = "/" }
{ print "file name is", $2 }
.fi
.ft R
.SH "SEE ALSO"
.IR "GAWK: Effective AWK Programming" ,
.IR filefuncs (3am),
.IR fnmatch (3am),
.IR fork (3am),
.IR inplace (3am),
.IR ordchr (3am),
.IR readfile (3am),
.IR revoutput (3am),
.IR rwarray (3am),
.IR time (3am).
.PP
.IR opendir (3),
.IR readdir (3),
.IR stat (2).
.SH AUTHOR
Arnold Robbins,
.BR arnold@skeeve.com .
.SH COPYING PERMISSIONS
Copyright \(co 2012, 2013, 2018, 2019, 2023
Free Software Foundation, Inc.
.PP
Permission is granted to make and distribute verbatim copies of
this manual page provided the copyright notice and this permission
notice are preserved on all copies.
.ig
Permission is granted to process this file through troff and print the
results, provided the printed document carries copying permission
notice identical to this one except for the removal of this paragraph
(this paragraph not being relevant to the printed manual page).
..
.PP
Permission is granted to copy and distribute modified versions of this
manual page under the conditions for verbatim copying, provided that
the entire resulting derived work is distributed under the terms of a
permission notice identical to this one.
.PP
Permission is granted to copy and distribute translations of this
manual page into another language, under the above conditions for
modified versions, except that this permission notice may be stated in
a translation approved by the Foundation.
.\" vim: set filetype=nroff :