# mv

_Peios / Using Peios / Peiosutils / Files and directories_

> Move or rename files and directories — including how a move handles a file's security descriptor depending on whether it crosses a file system.

`mv` moves files and directories from one place to another. Moving a file within the same directory, under a new name, is how you *rename* it.

```
mv [options] source dest
mv [options] source... directory
mv [options] -t directory source...
```

```
$ mv draft.txt report.txt                 # rename
$ mv report.txt notes.txt /home/jack/done/ # move into a directory
```

## A move is either a rename or a copy-and-delete

`mv` does its job in one of two ways, and which one decides what happens to the file's security.

**Within one file system, a move is a rename.** Nothing is copied: the file stays exactly where it physically is, and only its name and directory entry change. The file keeps its inode, and so it keeps its **security descriptor unchanged** — every owner, access rule, audit rule, and timestamp is exactly as before. A rename does not re-evaluate inheritance; a file does not pick up new rules just because it landed in a new directory.

**Across file systems, a move is a copy followed by a delete.** When the destination is on a different file system, `mv` cannot just rename — it copies the data to a new file on the destination, then removes the original. That new file is a genuinely new object, so, exactly as with [`cp`](/peios/using-peios/peiosutils/files-and-directories/cp.md), it gets a **fresh security descriptor inherited from the destination directory** unless you ask otherwise.

So: rename a file and its security is untouched; move it to another file system and the copy starts fresh.

## Preserving security on a cross-file-system move

For the copy-and-delete case, `mv` carries the same `--preserve` family that `cp` does — an identical set of options, behaving the same way. They let a cross-file-system move carry the source's owner, access rules, timestamps, and other attributes onto the new file instead of taking the destination directory's inherited default.

The full `--preserve` reference — the attribute list, `--sd`, `--sd-explicit`, `--preserve-all`, `--no-preserve`, and what happens when a preserve cannot be honoured — is on the [`cp`](/peios/using-peios/peiosutils/files-and-directories/cp.md) page. Everything there applies to `mv` unchanged.

On a same-file-system move the `--preserve` options have nothing to do: a rename already keeps every attribute, because it is the same file.

## Overwriting an existing destination

By default `mv` overwrites an existing destination. These options change that. When more than one of `-i`, `-f`, `-n` is given, the last one wins.

| Option | Effect |
|---|---|
| `-i`, `--interactive` | Ask before overwriting an existing file. |
| `-f`, `--force` | Do not prompt before overwriting. |
| `-n`, `--no-clobber` | Never overwrite an existing file. |
| `-u`, `--update[=WHICH]` | Overwrite only when the source is newer. `WHICH` can be `all`, `none`, or `older`. |
| `-b`, `--backup[=CONTROL]` | Make a backup of the destination before overwriting it. |

## Other options

| Option | Effect |
|---|---|
| `-t`, `--target-directory=DIR` | Move every source into `DIR`. |
| `-T`, `--no-target-directory` | Treat `dest` as a plain file even if it is a directory. |
| `--strip-trailing-slashes` | Strip any trailing slashes from each source argument. |
| `-v`, `--verbose` | Print each file as it is moved. |
| `--debug` | Explain in detail how each file was moved. Implies `-v`. |
| `--progress` | Show a progress bar. |

## Exit status

| Code | Meaning |
|---|---|
| `0` | Every file was moved successfully. |
| `1` | A file could not be moved. |

Related content:

- [cp](/peios/using-peios/peiosutils/files-and-directories/cp.md)
- [Files and directories](/peios/using-peios/peiosutils/files-and-directories/overview.md)
- [Security descriptors](/peios/security-fundamentals/security-descriptors/overview.md)