wiki.bash-hackers.org/syntax/ccmd/grouping_subshell.md
2023-04-15 23:53:05 +12:00

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====== Grouping commands in a subshell ======

===== Synopsis ===== ( )

===== Description ===== The list '''' is executed in a separate shell - a subprocess. No changes to the environment (variables etc...) are reflected in the "main shell".

===== Examples =====

Execute a command in a different directory. echo "$PWD" ( cd /usr; echo "$PWD" ) echo "$PWD" # Still in the original directory.

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

  • The subshell compound command is specified by POSIX.
  • Avoid ambiguous syntax. (((1+1))) # Equivalent to: (( (1+1) ))

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