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Revision 2 as of 2009-09-28 19:52:38
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Revision 3 as of 2009-09-28 20:01:34
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Comment: some more..
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 * <( ) >( ) process substitution is not defined by posix
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== Parameter Expansion == == Parameter Expansions ==
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list of expansions not defined by posix: List of expansions not defined by posix:
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== test ==
 
== Conditionals ==
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 * (( )) is not defined by posix

== Arithmetic ==

 * ++ -- are not defined by posix
 
== Redirections ==

 * >& and &> are not defined by posix
 * m>n- m<n- ie duplicating and closing a descriptor at the same time is not defined by posix
 * |& (bash4) is not defined by posix
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 * select is not defined by posix
 * shopt, and therefore all the options it provide, extglob, nullglob, dot glob etc ..are not defined by posix

This page is an attempt to list some of the most common bashisms ie features not defined by POSIX (ie don't work in dash). It probably won't be exhaustive. Note also we talk about "bashism" because this wiki is largely bash centric but a number of these extensions work in other shells like ksh or zsh.

Expansions

  • Brace Expansion, eg {1..10} is not defined by posix
  • <( ) >( ) process substitution is not defined by posix

Parameter Expansions

List of expansions not defined by posix:

  • ${name:n:l}
  • ${name/ }
  • ${!name}

Arrays

  • arrays are not defined by posix.

Conditionals

  • [[ is not defined by posix
  • == as an argument of test (aka [) is not defined by posix
  • < > to compare numbers as argument of test are not defined by posix, though dash implements them

  • -nt, -ot, -ef are not defined by posix
  • (( )) is not defined by posix

Arithmetic

  • ++ -- are not defined by posix

Redirections

  • >& and &> are not defined by posix

  • m>n- m<n- ie duplicating and closing a descriptor at the same time is not defined by posix

  • |& (bash4) is not defined by posix

Builtins

  • echo. posix doesn't define any options, use printf
  • printf "-v" is not defined by posix. also the %b and %q format are not defined by posix
  • read, the only option defined by posix is "-r"
  • select is not defined by posix
  • shopt, and therefore all the options it provide, extglob, nullglob, dot glob etc ..are not defined by posix

Bashism (last edited 2022-10-20 23:13:29 by larryv)