15. Parameter expansion¶
15.1. Simple usage¶
$PARAMETER${PARAMETER}
15.2. Indirection¶
${!PARAMETER}
15.3. Case modification¶
${PARAMETER^}${PARAMETER^^}${PARAMETER,}${PARAMETER,,}${PARAMETER~}${PARAMETER~~}
15.4. Variable name expansion¶
${!PREFIX*}${!PREFIX@}
15.5. Substring removal (also for filename manipulation!)¶
${PARAMETER#PATTERN}${PARAMETER##PATTERN}${PARAMETER%PATTERN}${PARAMETER%%PATTERN}
15.6. Search and replace¶
${PARAMETER/PATTERN/STRING}${PARAMETER//PATTERN/STRING}${PARAMETER/PATTERN}${PARAMETER//PATTERN}
15.7. String length¶
${#PARAMETER}
15.8. Substring expansion¶
${PARAMETER:OFFSET}${PARAMETER:OFFSET:LENGTH}
15.9. Use a default value¶
${PARAMETER:-WORD}${PARAMETER-WORD}
15.10. Assign a default value¶
${PARAMETER:=WORD}${PARAMETER=WORD}
15.11. Use an alternate value¶
${PARAMETER:+WORD}${PARAMETER+WORD}
15.12. Display error if null or unset¶
${PARAMETER:?WORD}${PARAMETER?WORD}