Craig White wrote:
On Mon, 2009-03-30 at 13:33 -0500, Justin Willmert wrote:
Craig White wrote:
I'm in my bash book and looking on web but can't seem to resolve this
simple problem.
$ if [ -n "grep A121 myfile.csv" ]; then echo "null"; fi
null
$ if [ -n "grep A125 myfile.csv" ]; then echo "null"; fi
null
A125 definitely is null when I just run the grep command in the quotes
but A121 definitely is not null.
What am I missing on the if/null operator here?
Craig
Have you tried
$ if [ -n $(grep A121 myfile.csv) ]; then echo "null"; fi
$ if [ -n $(grep A125 myfile.csv) ]; then echo "null"; fi
The double quotes make a string, but it looks like you which to be
executing grep which is accomplished by using the $() notation. You
could also use a pair of backticks surrounding the command.
----
I started with backticks...
$ if [ -n `grep A125 ARdebtorsmaster.csv` ]; then echo "null"; fi
null
$ if [ -n `grep A121 ARdebtorsmaster.csv` ]; then echo "null"; fi
bash: [: too many arguments
which interestingly is also the same problem that I get with your first
suggestion...
$ if [ -n $(grep A125 ARdebtorsmaster.csv) ]; then echo "null"; fi
null
$ if [ -n $(grep A121 ARdebtorsmaster.csv) ]; then echo "null"; fi
bash: [: too many arguments
and then of course, light bulb goes off...I have to figure out how to
get a basic exit code from grep, but seemingly the -s and the -q aren't
the answer.
They are. You want
if ! grep -q pat file; then echo null; fi
or my personal choich
grep -q pat file || echo null
--
Bill Davidsen <davidsen@xxxxxxx>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
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