wiki.bash-hackers.org/commands/builtin/readonly.md
2023-04-15 23:53:05 +12:00

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====== The readonly builtin command ======

===== Synopsis =====

readonly [-p] [-a] [-A] [-f] [NAME[=VALUE] ...]

===== Description =====

The ''readonly'' builtin command is used to mark variables or functions as read-only, which means unchangeable. This implies that it can't be unset anymore. A ''readonly'' variable may not be redefined in child scopes. A readonly global may not be redefined as a function local variable. Simple command environment assignments may not reference readonly variables.

==== Options ====

^Option ^Description ^ |''-a'' |refer to normal arrays | |''-A'' |refer to associative arrays | |''-f'' |refer to functions | |''-p'' |print all read-only variables or functions, ''-a'', ''-A'' and ''-f'' can be used to filter. The output is reusable as input |

An argument of ''%%--%%'' disables further option processing. ==== Return status ====

^Status ^Reason ^ |0 |no error | |!=0 |invalid option | |!=0 |invalid combination of options | |!=0 |a given ''NAME'' is invalid |

===== Examples =====

===== Portability considerations =====

  • in POSIX(r), only the ''-p'' option is specified

===== See also =====