My first Bash script : trouble with * 3354

On Tue, 12 Apr 2005 22:35:39 +0200, Vincent Schmid staggered into the Black Sun and said:

Check the bash scripting guide at little advanced for you right now.

? Why bother with making it readonly?

mkdir temp if test -e temp-* ; then echo "not empty" ; else echo "empty" ; fi touch temp-test if test -e temp-* ; then echo "not empty" ; else echo "empty" ; fi touch temp-test2 if test -e temp-* ; then echo "not empty" ; else echo "empty" ; fi barf

...test expects *one* operand. * can expand to multiple operands. So...

...er, what are you trying to do here?

The shell expands glob patterns. "echo *" will show all the files in the current directory. "echohome-*" will show all the files inhome. When you do "wc *.txt" , the shell expands the * , and what actually gets executed is "wc file1.txt file2.txt file3.txt" . This is how things have worked for a long, long time.

You could always do it like so:

R=`lspath-to-somewhere wc -l` if $R == "0" ; then echo "empty" ; else echo "not empty" ; fi

...bash's syntax for logical operations like these is a bit annoying IMHO, but you can do it. Note that this fails if there are files whose names begin with a . in the directory. There is an option you can feed to ls that'll solve that problem; that option is in the man page and is not -a. There may be more efficient ways to do this, but this does seem to work.

bash is useful, but there are things that are easier to do in other scripting languages. Text manipulation, math, and semi-complex data structures are easier to deal with in Perl than they are in bash, f'rexample. Just make sure to pick the right language for the problem you're trying to solve, and you'll be happier and get the job done faster. HTH,

-- Matt GThere is no Darkness in Eternity-But only Light too dim for us to see Brainbench MVP for Linux Admin mail: TRAP + SPAN don't belong