Gene Heskett wrote at 12:04 -0400 on Jul 21, 2010:
> Greetings all;
>
> My catchup script seems to be working with 2 exceptions, first being that I
> am not getting any emails from it, so I installed dnsmasq to see if that
> fixes that.
>
> 2nd, each pass through my catchup script loop elicits an error warning from
> the main script:
>
> ./flush.sh: line 173: [: !=: unary operator expected
>
> from that script:
> # or are we running as flush.sh
>
> if [ $0 == "./flush.sh" ] || [ $0 == "${MYDIR}/flush.sh" ] || [ $0 ==
> "flush.sh" ]; then
== is a bash-ism. Get in the habit of using = for posix compliance.
You'll thank yourself when you might have to run a script on a system
that doesn't use bash for sh(1) (bsd's, solaris).
"Always" put quotes around vars ("$foo", "$0", etc.) since vars
can contain strings with spaces confusing test(1) (aka [).
You don't need quotes around literals that you have written
("./flush.sh" in your case above). So in '[ $0 == "./flush.sh" ]',
you have your quoting backwards (with respect to defensive script
writing).
> # we don't want amflush to disconnect or ask questions
> if [ `/bin/ls /dumps` != "" ] ; then <-------------------line 173
> echo "Backup script running amflush -bf $CONFIGNAME " |tee -
> a >> $LOG
Same deal (use quotes) for back-tick expressions (`cmd` or $(cmd)).
And that's your problem. Looks like `ls /dumps` is providing empty
output.
example:
if [ `echo 1 2` = 1 ]; then echo y; else echo n; fi
[: 1: unexpected operator
or
bash -c 'if [ `echo -n` != "" ]; then echo y; else echo n; fi'
bash: [: !=: unary operator expected
if [ "`echo 1 2`" = 1 ]; then echo y; else echo n; fi
n
