--- name: "filefuncs" section: "3am" platform: "linux" package: "gawk" version: "5.4.1-1" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/filefuncs" --- # filefuncs(3am) provide some file related functionality to gawk ## NAME filefuncs - provide some file related functionality to gawk ## SYNOPSIS `@load "filefuncs"` `result = chdir("/some/directory")` `result = stat("/some/path", statdata [, follow])` `flags = or(FTS_PHYSICAL, ...)`\ `result = fts(pathlist, flags, filedata)` `result = statvfs("/some/path", fsdata)` ## DESCRIPTION The *filefuncs* extension adds several functions that provide access to file-related facilities. ### chdir() The **chdir()** function is a direct hook to the [*chdir*(2)](/chdir/2.md) system call to change the current directory. It returns zero upon success or less than zero upon error. In the latter case it updates **ERRNO**. ### stat() The **stat()** function provides a hook into the [*stat*(2)](/stat/2.md) system call. It returns zero upon success or less than zero upon error. In the latter case it updates **ERRNO**. By default, it uses [*lstat*(2)](/lstat/2.md). However, if passed a third argument, it uses [*stat*(2)](/stat/2.md), instead. In all cases, it clears the **statdata** array. When the call is successful, **stat()** fills the **statdata** array with information retrieved from the filesystem, as follows: - **statdata\["name"\]** The name of the file, equal to the first argument passed to **stat()**. - **statdata\["dev"\]** Corresponds to the *st\_dev* field in the *struct stat*. - **statdata\["ino"\]** Corresponds to the *st\_ino* field in the *struct stat*. - **statdata\["mode"\]** Corresponds to the *st\_mode* field in the *struct stat*. - **statdata\["nlink"\]** Corresponds to the *st\_nlink* field in the *struct stat*. - **statdata\["uid"\]** Corresponds to the *st\_uid* field in the *struct stat*. - **statdata\["gid"\]** Corresponds to the *st\_gid* field in the *struct stat*. - **statdata\["size"\]** Corresponds to the *st\_size* field in the *struct stat*. - **statdata\["atime"\]** Corresponds to the *st\_atime* field in the *struct stat*. - **statdata\["mtime"\]** Corresponds to the *st\_mtime* field in the *struct stat*. - **statdata\["ctime"\]** Corresponds to the *st\_ctime* field in the *struct stat*. - **statdata\["rdev"\]** Corresponds to the *st\_rdev* field in the *struct stat*. This element is only present for device files. - **statdata\["major"\]** Corresponds to the *st\_major* field in the *struct stat*. This element is only present for device files. - **statdata\["minor"\]** Corresponds to the *st\_minor* field in the *struct stat*. This element is only present for device files. - **statdata\["blksize"\]** Corresponds to the *st\_blksize* field in the *struct stat*, if this field is present on your system. (It is present on all modern systems that we know of.) - **statdata\["pmode"\]** A human-readable version of the mode value, such as printed by [*ls*(1)](/ls/1.md). For example, **"-rwxr-xr-x"**. - **statdata\["linkval"\]** If the named file is a symbolic link, this element will exist and its value is the value of the symbolic link (where the symbolic link points to). - **statdata\["type"\]** The type of the file as a string. One of **"file"**, **"blockdev"**, **"chardev"**, **"directory"**, **"socket"**, **"fifo"**, **"symlink"**, **"door"**, or **"unknown"**. Not all systems support all file types. ### fts() The **fts()** function provides a hook to the [*fts*(3)](/fts/3.md) set of routines for traversing file hierarchies. Instead of returning data about one file at a time in a stream, it fills in a multi-dimensional array with data about each file and directory encountered in the requested hierarchies. The arguments are as follows: - **pathlist** An array of filenames. The element values are used; the index values are ignored. - **flags** This should be the bitwise OR of one or more of the following predefined flag values. At least one of **FTS\_LOGICAL** or **FTS\_PHYSICAL** must be provided; otherwise **fts()** returns an error value and sets **ERRNO**. - **FTS\_LOGICAL** Do a \`\`logical'' file traversal, where the information returned for a symbolic link refers to the linked-to file, and not to the symbolic link itself. This flag is mutually exclusive with **FTS\_PHYSICAL**. - **FTS\_PHYSICAL** Do a \`\`physical'' file traversal, where the information returned for a symbolic link refers to the symbolic link itself. This flag is mutually exclusive with **FTS\_LOGICAL**. - **FTS\_NOCHDIR** As a performance optimization, the [*fts*(3)](/fts/3.md) routines change directory as they traverse a file hierarchy. This flag disables that optimization. - **FTS\_COMFOLLOW** Immediately follow a symbolic link named in **pathlist**, whether or not **FTS\_LOGICAL** is set. - **FTS\_SEEDOT** By default, the [*fts*(3)](/fts/3.md) routines do not return entries for \`\`.'' and \`\`..''. This option causes entries for \`\`..'' to also be included. (The AWK extension always includes an entry for \`\`.'', see below.) - **FTS\_XDEV** During a traversal, do not cross onto a different mounted filesystem. - **FTS\_SKIP** When set, causes top level directories to not be descended into. - **filedata** The **filedata** array is first cleared. Then, **fts()** creates an element in **filedata** for every element in **pathlist**. The index is the name of the directory or file given in **pathlist**. The element for this index is itself an array. There are two cases. - The path is a file. In this case, the array contains two or three elements: - **"path"** The full path to this file, starting from the \`\`root'' that was given in the **pathlist** array. - **"stat"** This element is itself an array, containing the same information as provided by the **stat()** function described earlier for its **statdata** argument. The element may not be present if [*stat*(2)](/stat/2.md) for the file failed. - **"error"** If some kind of error was encountered, the array will also contain an element named **"error"**, which is a string describing the error. - The path is a directory. In this case, the array contains one element for each entry in the directory. If an entry is a file, that element is as for files, just described. If the entry is a directory, that element is (recursively), an array describing the subdirectory. If **FTS\_SEEDOT** was provided in the flags, then there will also be an element named **".."**. This element will be an array containing the data as provided by **stat()**. In addition, there will be an element whose index is **"."**. This element is an array containing the same two or three elements as for a file: **"path"**, **"stat"**, and **"error"**. The **fts()** function returns 0 if there were no errors. Otherwise it returns -1. ### statvfs() The **statvfs()** function provides a hook into the [*statvfs*(2)](/statvfs/2.md) system call on systems that supply this system call. It returns zero upon success or less than zero upon error. In the latter case it updates **ERRNO**. When the call is successful, **statvfs()** fills the **fsdata** array with information retrieved about the filesystem, as follows: - **fsdata\["bsize"\]** Corresponds to the **bsize** member in the *struct statvfs*. - **fsdata\["frsize"\]** Corresponds to the *f\_frsize* member in the *struct statvfs*. - **fsdata\["blocks"\]** Corresponds to the *f\_blocks* member in the *struct statvfs*. - **fsdata\["bfree"\]** Corresponds to the *f\_bfree* member in the *struct statvfs*. - **fsdata\["bavail"\]** Corresponds to the *f\_bavail* member in the *struct statvfs*. - **fsdata\["files"\]** Corresponds to the *f\_files* member in the *struct statvfs*. - **fsdata\["ffree"\]** Corresponds to the *f\_ffree* member in the *struct statvfs*. - **fsdata\["favail"\]** Corresponds to the *f\_favail* member in the *struct statvfs*. - **fsdata\["fsid"\]** Corresponds to the *f\_fsid* member in the *struct statvfs*. This member is not available on all systems. - **fsdata\["flag"\]** Corresponds to the *f\_flag* member in the *struct statvfs*. - **fsdata\["namemax"\]** Corresponds to the *f\_namemax* member in the *struct statvfs*. ## NOTES The AWK **fts()** extension does not exactly mimic the interface of the [*fts*(3)](/fts/3.md) routines, choosing instead to provide an interface that is based on associative arrays, which should be more comfortable to use from an AWK program. This includes the lack of a comparison function, since *gawk* already provides powerful array sorting facilities. While an *fts\_read()*-like interface could have been provided, this felt less natural than simply creating a multi-dimensional array to represent the file hierarchy and its information. Nothing prevents AWK code from changing the predefined **FTS\_***xx* values, but doing so may cause strange results when the changed values are passed to **fts()**. ## BUGS There are many more file-related functions for which AWK interfaces would be desirable. It's not clear why I thought adding **FTS\_SKIP** was a good idea. ## EXAMPLE See **test/fts.awk** in the *gawk* distribution for an example. ## SEE ALSO *GAWK: Effective AWK Programming*, and the man pages for the other extensions shipped with *gawk*. [*chdir*(2)](/chdir/2.md), [*fts*(3)](/fts/3.md), [*stat*(2)](/stat/2.md), [*statvfs*(2)](/statvfs/2.md). ## AUTHOR Arnold Robbins, **arnold@skeeve.com**. ## COPYING PERMISSIONS Copyright © 2012, 2013, 2018, 2019, 2026, Free Software Foundation, Inc. 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. 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