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.TH READDIR 3am "Sep 11 2012" "Free Software Foundation" "GNU Awk Extension Modules"
.SH NAME
readdir \- directory input parser for gawk
.SH SYNOPSIS
.ft CW
@load "readdir"
.sp
readdir_do_ftype("stat") # or "dirent" or "never"
.ft R
.SH DESCRIPTION
The
.I readdir
extension
adds an input parser for directories, and
adds a single function named
.BR readdir_do_ftype() .
.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 at least two fields: the inode number and the
filename, separated by a forward slash character.
On systems where the directory entry contains the file type, the record
has a third field which 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,
.B s
for a socket, and
.B u
(unknown) for anything else.
.PP
On systems without the file type information, calling
.B readdir_do_ftype("stat")
causes the extension to use
.IR lstat (2)
to retrieve the appropriate information. This is not the default, since
.IR lstat (2)
is a potentially expensive operation. By calling
.B readdir_do_ftype("never")
one can ensure that the file type
information is never displayed, even when readily available in the
directory entry.
.PP
The third option,
.BR readdir_do_ftype("dirent") ,
takes file type information from the directory entry, if it is available.
This is the default on systems that supply this information.
.PP
The
.B readdir_do_ftype()
function will set
.B ERRNO
if called without arguments or with invalid arguments.
.SH NOTES
On GNU/Linux systems, there are filesystems that don't support the
.B d_type
entry (see
.IR readdir (3)),
and so the file type is always
.BR u .
Therefore, using
.B readdir_do_ftype("stat")
is advisable even on GNU/Linux systems. In this case, the
.I readdir
extension will fall back to using
.IR lstat (2)
when it encounters an unknown file type.
... .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 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
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.
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