A subshell is spawn by using a ` ( the [~] key ) surrounding the desired
command.
To the best of my knowledge an "if" conditional test in a bash shell ( if
] then fi ) cannot
drop into a subshell within the brackets [].
However, two ways I know how to solve your question.
1)
#!/bin/sh
...
$VARIABLE_NAME="`lsmod |grep $module`"
# Notice the "`", and the variable is surrounded by double quotes.
# If the subshell command generates several lines, it does goofy things
# to your terminal. Double quotes keep it contained.
if [ -n/-z "$VARIABLE_NAME" ] # Double quotes again
then
do_stuff...
fi
2)
#!/bin/sh
...
test -n/-z "`lsmod |grep $module`" ||/&& {do_stuff...}
# Notice the "`" for the subshell command, and it is surrounded by double
quotes
# Pick either || or && to determine if the condition is met or not met and
then "do_stuff".
Finally, a subtle gotcha, a variable in single quotes will tell the shell to
ignore the contents within,
and double quotes will tell the shell to interpret within the quotes...
For more info, from a bash shell command line:
]# help test
]# help if
]# help [
Hope this helps,
Ken
> Date: Wed, 17 Jul 2002 20:19:36 -0500 (CDT)
> Subject: Re: Question on 'if' in bash script
>
> to access a command from within shell, enclose it in ` `
> as
> for files in `cat some.list`
> do
> blah
> etc....
>
> On Wed, 17 Jul 2002, David Busby wrote:
>
> > How would I construct the "if" to see if a module is loaded
> >
> > I've tried
> >
> > if [ -n "lsmod |grep $module" ]
> > as well as
> > if [ -z "lsmod |grep $module" ]
> >
> > I can't get either to work...what am I doing wrong?
> >
> > /b
> >
> >
> >
>
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