Debian Almquist shell
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Debian Almquist shell (dash) is a POSIX-compliant Unix shell, much smaller than bash. It requires less disk space but is also less feature rich.
Dash is a direct descendant of the NetBSD version of the Almquist Shell (ash). It was ported to Linux by Herbert Xu in early 1997. It was renamed to dash in 2002.
Dash, like ash, executes scripts faster than bash and depends on fewer libraries. It is believed to be more reliable in case of upgrade problems or disk failures. dash may be used as:
- shell on the installation floppy disks
- root user shell
- /bin/sh replacement
- a testing environment for shell scripts to verify their compatibility with POSIX syntax
Dash is a modern replacement for ash in Debian and is expected to be the default /bin/sh for Debian Lenny.[1] Since the 6.10 release in October 2006, dash is also the default /bin/sh in Ubuntu[2]. However, the transition in Ubuntu to making dash /bin/sh broke numerous shell scripts that relied upon bash-specific functionality.[3] [4] To avoid this problem, scripts were modified to be compatible with the appropriate standard or explicitly declared their use of "bashisms" with the line:
#!/bin/bash
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