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From: jik@athena.mit.edu (Jonathan I. Kamens)
Newsgroups: comp.unix.shell
Subject: Re: testing if a file is present
Message-ID: <1990Nov21.191638.19469@athena.mit.edu>
Date: 21 Nov 90 19:16:38 GMT
References: <ger.659126250@prisma>
Sender: daemon@athena.mit.edu (Mr Background)
Reply-To: jik@athena.mit.edu (Jonathan I. Kamens)
Distribution: comp.unix
Organization: Massachusetts Institute of Technology
Lines: 38

In article <ger.659126250@prisma>, ger@prisma.cv.ruu.nl (Ger Timmens) writes:
|> Can anybody tell me how I can verify
|> whether a file exists or not ?
|> I want to move files and only when
|> they exist ! mv "file" gives an
|> error message if "file" not exists

  It depends on the shell you're using.  In csh or tcsh:

	if (-e filename) then
		... stuff if filename exists ...
	endif

In sh, with either a test built-in named "[" or a link in your filesystem
called "[" pointing to the test program:

	if [ -r filename ]; then
		... stuff if filename exists ...
	fi

Some versions of test allow "-e" to test for existence, instead of "-r" to
test for existence and readibility, but mine doesn't, so I use "-r" instead of
"-e" above.  In sh without "[":

	if test -r filename; then
		... stuff if filename exists
	fi

Ksh and bash probably do things the same way sh does, using "[".

  In the future, it would help if you would give more details, such as the
shell you're using, when you ask questions like this.
		
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