Comments on: Increasing command line productivity in the bash shell PT: II http://www.digitalprognosis.com/linuxtips/increasing-command-line-productivity-in-the-bash-shell-pt-ii/ Unix and Linux Systems Administration from the trenches… by Jeff Schroeder Fri, 20 Aug 2010 05:24:35 -0400 hourly 1 http://wordpress.org/?v=3.0.1 By: Jeff http://www.digitalprognosis.com/linuxtips/increasing-command-line-productivity-in-the-bash-shell-pt-ii/comment-page-1/#comment-257 Jeff Thu, 17 Jul 2008 12:10:26 +0000 http://digitalprognosis.com/linuxtips/?p=16#comment-257 From this post, "${parameter:-word} Substitute word if parameter is null or non-set. Otherwise, use $parameter as normal." You bring up a good point, but I already said the same thing :) From this post, “${parameter:-word} Substitute word if parameter is null or non-set. Otherwise, use $parameter as normal.”

You bring up a good point, but I already said the same thing :)

]]> By: Rasta Freak http://www.digitalprognosis.com/linuxtips/increasing-command-line-productivity-in-the-bash-shell-pt-ii/comment-page-1/#comment-256 Rasta Freak Thu, 17 Jul 2008 10:26:06 +0000 http://digitalprognosis.com/linuxtips/?p=16#comment-256 Nice tips, Jeff. I'd like to see more of this :) Anyway, just one note: when using parameter substitution (:-, :+, :=), i think that one more thing needs to be said: if you use it with ":" sign (:-, :+, :=) then it checks if parameter is unset (set) OR null (if var is set to NULL value, var is considered unset). If you use it without ":" character (-,+,=), it checks only if parameter is set (unset) (if var is set to NULL value, var is considered set). Nice tips, Jeff. I’d like to see more of this :)
Anyway, just one note:

when using parameter substitution (:-, :+, :=), i think that one more thing needs to be said: if you use it with “:” sign (:-, :+, :=) then it checks if parameter is unset (set) OR null (if var is set to NULL value, var is considered unset). If you use it without “:” character (-,+,=), it checks only if parameter is set (unset) (if var is set to NULL value, var is considered set).

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