dash

Run script

$ dash [script.sh]

$ dash -c '[command]'

$ dash -n [script.sh]

$ dash -x [script.sh]

$ dash -v [script.sh]

$ dash -i

dash [options] [script-file [arguments]]

dash is the Debian Almquist Shell, a POSIX-compliant /bin/sh implementation designed for efficiency and standards compliance. It is significantly faster and smaller than bash, making it ideal for running shell scripts and system initialization.
The shell prioritizes script execution speed, startup time, and minimal memory footprint over interactive features. It's approximately 4x faster than bash for script execution, which is why Debian and Ubuntu use it as the default /bin/sh.
dash is derived from NetBSD's ash (Almquist shell), which itself was created as a BSD-licensed replacement for the original Bourne shell. It implements the POSIX shell specification strictly, without bash extensions like arrays, [[ ]] conditionals, or process substitution.
The shell is primarily used for system scripts, package manager scripts, and situations where POSIX compliance and performance matter more than advanced interactive features.

-c string

Read commands from string

Read commands from stdin

Interactive mode

Login shell

Disable filename expansion (noglob)

Check syntax only (noexec)

Error on undefined variables (nounset)

Print input lines (verbose)

Print commands before execution (xtrace)

Exit on error (errexit)

Ignore EOF in interactive mode

Show help

Show version

Approximately 4x faster than bash for script execution.

Strictly POSIX-compliant. Bash-specific features not supported:
- `[[ ... ]]` conditionals
- Process substitution `<()`
- Arrays
- Non-standard globbing

Scripts using bash-isms will fail. Use `#!/bin/bash` for bash-specific scripts. dash is /bin/sh on Debian/Ubuntu.

bash(1), sh(1), zsh(1)