READLINK(1)

SYNOPSIS

readlink [-n|-z] file…

readlink -f|-e|-m file…

DESCRIPTION

Writes the target (content) of each file, which must be a symbolic link, followed by a new-line (0xA), to the standard output stream.

With -fem, canonicalises the path to files by replacing itself with realpath(1).

OPTIONS

-n, --no-newline: Write nothing after the target of each file.
-z, --zero: Write a NUL after the target of each file.

-f, --canonicalize: Replace with realpath [-z] file…
-e, --canonicalize-existing: Replace with realpath -e [-z] file…
-m, --canonicalize-missing: Replace with realpath -m [-z] file…

EXIT STATUS

1 if a file wasn't a symbolic link. An error is also issued to the standard error stream in this case.

EXAMPLES

$ ls -l store
lrwxrwxrwx 1 root root 25 2020-03-16  store -> /mnt/filling/store/cicada
$ readlink store
/mnt/filling/store/cicada

STANDARDS

Conforms to IEEE Std 1003.1-2024 (“POSIX.1”). -zfem and more than one file are extensions, compatible with the GNU system.

Appeared fully-formed in OpenBSD 2.2 (1997-12) (appears in time for OpenBSD 2.1, saying it targets OpenBSD 2.1, but is not tagged for inclusion in OpenBSD 2.1, and is not included in OpenBSD 2.1 distribution tarballs; the first tag is for OpenBSD 2.2 and it features in OpenBSD 2.2 tarballs) as readlink(1) ("display target of symbolic link on standard output"), synopsised as

readlink [-fn] file

-n and successful behaviour is as present-day, but errors aren't:

If readlink is invoked with an argument other than the pathname of a symbolic link it exits with a non-zero exit code and without printing anything.

-f replaces readlink(2) with realpath(3); which is like this implementation's readlink -e (realpath -e). A realpath(3) failure dumps uninitialised data and a newline (unless -n). The result of -f is truncated at the length of file; this is fixed in OpenBSD 2.4 (1998-12).

OpenBSD 4.1 (2007-05) properly exits with an error if realpath(3) failed.

NetBSD 2.0 (2004-12) adds readlink to stat(1) ("display file status"), "for similarity to OpenBSD", synopsising it as

readlink [-n] [file ...]

which is like OpenBSD readlink, but for any number of files.

NetBSD 4.0 (2007-12) adds -f, same as OpenBSD.

NetBSD 6.0 (2012-10) sees a SYNOPSIS of

readlink [-fnqsv] [file ...]

-qs is the default (errors aren't logged) and -v reverses this (errors to the standard error stream).

NetBSD 10 splits the manuals into stat(1)/readlink(1).

coreutils 4.5.5 (2003-02) adds readlink(1) ("display value of a symbolic link"), synopsised as:

readlink [OPTION] FILE

where OPTIONS is actually any of -fnqsv 🙄 This is described as equivalent to NetBSD 10; it's unclear if -f is as present-day or as NetBSD 10.

coreutils 5.3.0 (2005-01) adds -em (and notes correcting -f), making them as present-day.

coreutils 8.21 (2013-02) "now supports multiple arguments" and adds -z. -n is ignored with multiple files.

NAME