testing if a file is present
Jonathan I. Kamens
jik at athena.mit.edu
Thu Nov 22 06:16:38 AEST 1990
In article <ger.659126250 at prisma>, ger at 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.
--
Jonathan Kamens USnail:
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jik at Athena.MIT.EDU Allston, MA 02134
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