[Swan-dev] understanding output of the tests

D. Hugh Redelmeier hugh at mimosa.com
Wed Apr 2 19:30:54 EEST 2014

| From: Paul Wouters <paul at nohats.ca>

| Why are the quotes needed when using : ?

: is really a command that does nothing, rather than a comment.
So redirection and variable expansion are done on the operands.

	: >file
would actually create an empty file "file".

	: '>file'
would act like
	# >file

(# was introduced with the Bourne Shell.  The original UNIX shell
(before the 7th Edition) didn't have it.  ":" served two purposes in
the old shell: comments and labels (for control flow).  The Bourne
Shell was a great advance in so many ways.)

More information about the Swan-dev mailing list