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command | meaning |
---|---|
${parameter:-defaultValue} | Get default shell variables value |
${parameter:=defaultValue} | Set default shell variables value |
${parameter:?"Error Message"} | Display an error message if parameter is not set |
${#var} | Find the length of the string |
${var%pattern} | Remove from shortest rear (end) pattern |
${var%%pattern} | Remove from longest rear (end) pattern |
${var:num1:num2} | Substring |
${var#pattern} | Remove from shortest front pattern |
${var##pattern} | Remove from longest front pattern |
${var/pattern/string} | Find and replace (only replace first occurrence) |
${var//pattern/string} | Find and replace all occurrences |
${!prefix*} | Expands to the names of variables whose names begin with prefix. |
${var,} | Convert first character to lowercase. |
${var,pattern} | Convert only if the pattern match |
${var,,} | Convert all characters to lowercase. |
${var,,pattern} | Convert only if the pattern match |
${var^} | Convert first character to uppercase. |
${var^pattern} | Convert only if pattern match |
${var^^} | Convert all character to uppercase.} |
${var^^pattern} | Convert only if pattern match |