Now I am really confused!
This works:
#!/bin/bash
if [ -z $1 ]; then
echo ''
echo "format is $0 'math equation'"
echo "i.e. $0 (2+2)*3"
echo ''
exit
fi
echo $1 | /usr/bin/bc -l
If you notice the only change I made was go with the better test for a
blank variable.
At least I though.
The problem is with the if condition. I don't understand why, but here
are the conditions. Pay close attention of the spaces around the '[]'
The following work when argument is NOT given
if [$1 == '']
if [ $1 == '']
if [ -z == '' ]
The above, all give error when an argument is added
Any other combination fail when and argumet is NOT given, with the
exception of Bret's:
if [ -z $1 ]
Like I said I don't understand it, but it works.
david
P.S. I agree the '2&>/dev/null is strange
On 11 Dec 2002, Bret Hughes wrote:
> On Wed, 2002-12-11 at 12:05, dbrett wrote:
> > I have a bash to math calucations. It works but also complains about the
> > last line, even though it works.
> >
> > Any ideas how to fix the problem or at least not see the error message and
> > still work.
> >
> > #!/bin/bash
> >
> > if [$1 == '']; then
> > echo ''
> > echo "format is $0 'math equation'"
> > echo "i.e. $0 (2+2)*3"
> > echo ''
> > exit
> > fi
> >
> > echo $1 | /usr/bin/bc -l &2>/dev/null
> >
>
> only way I can get it to work is to quote the equation and fix the
> syntax of the test statement.
>
> #!/bin/bash
> if [ -z $1 ]; then # spaces inside the [ ] -z test for null string
>
> echo ''
> echo "format is $0 'math equation'"
> echo "i.e. $0 (2+2)*3"
> echo ''
> exit
> fi
>
> echo $1 | /usr/bin/bc -l 2>/dev/null
>
> Roberts suggestion of dropping the &2> in favor of 2> fixed a really
> funky newline thing I will have to figure out some day :)
> [bhughes@bretsony bhughes]$ bc.test.sh
>
> format is ./bc.test.sh 'math equation'
> i.e. ./bc.test.sh (2+2)*3
>
> [bhughes@bretsony bhughes]$ bc.test.sh (2+2)*3
> bash: syntax error near unexpected token `(2+2)'
> [bhughes@bretsony bhughes]$
> [bhughes@bretsony bhughes]$ bc.test.sh '(2+2)*3'
> 12
>
> HTH
>
> Bret
>
>
>
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