mktemp

Create temporary files or directories safely and print their names

TLDR

Create an empty temporary file and print its path

$ mktemp

Create a temporary file in a custom directory

$ mktemp -p [/path/to/directory]

Use a custom template (Xs replaced with random characters)

$ mktemp [/tmp/example.XXXXXXXX]

Create a temporary file with a specific suffix

$ mktemp --suffix [.txt]

Create an empty temporary directory

$ mktemp -d

Dry run: print name without creating

$ mktemp -u

SYNOPSIS

mktemp [-d] [-u] [-q] [-p dir] [--suffix suff] [template]

mktemp creates temporary files or directories safely and prints their paths. The template must include at least 3 consecutive X characters in its final component, which are replaced with random alphanumeric characters to ensure uniqueness.When no template is provided, mktemp defaults to tmp.XXXXXXXXXX in the system temp directory. Files are created with u+rw permissions and directories with u+rwx, both modified by umask.The safe creation prevents race conditions where another process might create a file between checking for existence and creating. This is critical for secure script writing.

PARAMETERS

-d, --directory

Create a directory instead of a file.

-u, --dry-run

Print name without creating anything (unsafe; see CAVEATS).

-q, --quiet

Suppress error messages on creation failure.

-p dir, --tmpdir[=dir]

Create temporary file relative to the specified directory; defaults to $TMPDIR or /tmp.

-t

Interpret template as a filename relative to the temp directory (deprecated).

--suffix suff

Append suffix to template; suffix must not contain slashes.

INSTALL

sudo apt install coreutils

sudo dnf install coreutils

sudo pacman -S coreutils

sudo apk add coreutils

sudo zypper install coreutils

brew install coreutils

nix profile install nixpkgs#coreutils

CAVEATS

The -u (dry-run) option is unsafe for production scripts because another process could create the file between printing the name and actual use. Always let mktemp create the file directly. Temporary files persist until explicitly deleted; clean up in scripts using trap.

HISTORY

mktemp originated in OpenBSD and was later adopted by other systems. The GNU version is part of coreutils. The command provides a safe interface to the mkstemp(3) and mkdtemp(3) library functions.