bash: Special Builtins
1
1 4.4 Special Builtins
1 ====================
1
1 For historical reasons, the POSIX standard has classified several
1 builtin commands as _special_. When Bash is executing in POSIX mode,
1 the special builtins differ from other builtin commands in three
1 respects:
1
1 1. Special builtins are found before shell functions during command
1 lookup.
1
1 2. If a special builtin returns an error status, a non-interactive
1 shell exits.
1
1 3. Assignment statements preceding the command stay in effect in the
1 shell environment after the command completes.
1
1 When Bash is not executing in POSIX mode, these builtins behave no
1 differently than the rest of the Bash builtin commands. The Bash POSIX
1 mode is described in ⇒Bash POSIX Mode.
1
1 These are the POSIX special builtins:
1 break : . continue eval exec exit export readonly return set
1 shift trap unset
1