realpath
realpath resolves a path to its canonical form: absolute, with every symbolic link followed and every . and .. component removed. Given any path, it tells you the one true location it refers to.
realpath [options] file...
$ realpath ../work/./notes.txt
/data/projects/jack/notes.txt
A single file can be named many ways — through links, through relative paths, with redundant components. realpath reduces all of them to the single canonical path, which makes it the right tool for comparing two paths, or for turning a path a user typed into one a script can rely on.
How much must exist #
By default realpath requires every component of the path except the last to exist. These options change that requirement:
| Option | Existence requirement |
|---|---|
| (default) | Every component except the last must exist. |
-e, --canonicalize-existing | Every component must exist — including the final one. |
-m, --canonicalize-missing | No component need exist. The path is canonicalised purely as text where it cannot be walked. |
How symbolic links are handled #
| Option | Effect |
|---|---|
-P, --physical | Resolve each symbolic link as it is encountered. This is the default. |
-L, --logical | Resolve .. components before resolving the symbolic links they follow. |
-s, --strip, --no-symlinks | Do not resolve symbolic links at all — only remove . and .. components. The result is canonical as text, but a link in the path is left as-is. |
Output options #
| Option | Effect |
|---|---|
--relative-to=DIR | Print the result as a path relative to DIR instead of as an absolute path. |
--relative-base=DIR | Print an absolute path, unless the result lies inside DIR, in which case print it relative to DIR. |
-z, --zero | End each output line with a NUL character instead of a newline. |
-q, --quiet | Do not print a warning when a path is invalid. The exit status still reports the failure. |
realpath and readlink #
readlink with -f/-e/-m does the same canonicalising job. The difference is focus: readlink is primarily for reading a single link's target, with canonicalising as an extra; realpath is built for canonicalising and carries the richer option set — relative output, the symlink-handling modes, the strip-only mode. Use realpath when canonicalising is the actual goal.
Exit status #
| Code | Meaning |
|---|---|
0 | Every path was resolved and printed. |
1 | A path could not be resolved under the chosen options. |