C Shell Scripting/Modifiers

Variable Modifiers In C shell, the path value obtained from a variable can be modified before it is used into a command or expression. Variable modifiers are given after a colon (:) at the end of a variable. The meaning of the modifiers are as follows: :h returns the directory of a path (aka "head") :t returns the filename of a path (aka "tail") :r returns the directory and filename without the last extension (aka "root") :e returns the extension of the path (aka "end") For example, using this script: #!/bin/csh -f set file = /usr/joe/backup.tar.gz echo $file:h echo $file:t echo $file:r echo $file:e echo $file:t:r:r echo $file:h:h will produce this: /usr/joe backup.tar.gz /usr/joe/backup.tar gz backup /usr Lessons Variable modifiers are convenient to manipulate paths within the script. tcsh allows chaining modifiers together but some implementations only support one modifier at a time. Concatenating a variable with a colon character requires code such as $var"": or ${var}: to avoid a "Bad : modifier" error.