case

case

 

value

 

in

     

pattern1



)

 

cmds1



;;

     

pattern2



)

 

cmds2



;;

     .     .     . 

esac

Execute the first set of commands ( cmds1 ) if value matches pattern1 , execute the second set of commands ( cmds2 ) if value matches pattern2 , etc. Be sure the last command in each set ends with ;; . value is typically a positional parameter or other shell variable. cmds are typically UNIX commands, shell programming commands, or variable assignments. Patterns can use file generation metacharacters. Multiple patterns (separated by | ) can be specified on the same line; in this case, the associated cmds are executed whenever value matches any of these patterns. See below and under eval for examples. (Note: the Korn shell allows pattern to be preceded by an optional open parenthesis, as in ( pattern ) . It's useful for balancing parentheses inside a $( ) construct.)

Examples

Read first command-line argument and take appropriate action:

case $1 in	#match the first arg     no|yes) response=1;;     -[tT])  table=TRUE;;     *)      echo "unknown option"; exit 1;; esac

Read user-supplied lines until user exits:

while :	# Null command; always true do    echo "Type . to finish ==> \c"    read line    case "$line" in       .) echo "Message done"          break ;;       *) echo "$line" >> $message ;;    esac done