test command looks strange... - Shell Programming and Scripting

jjinno · #1 11-02-2007

I just ran into this today, and don't know what to make of it...

Code:

if test x$SERVER = x
then
        echo $USAGE
        exit 1
fi

I know what everything in there does, except for the 'x' jazz...

porter · #2 11-02-2007

Quote:

Originally Posted by jjinno

I just ran into this today, and don't know what to make of it...

Code:

if test x$SERVER = x
then
        echo $USAGE
        exit 1
fi

I know what everything in there does, except for the 'x' jazz...

It is effecitvely doing

Code:

if test "$SERVER" = ""
then
     ....

rather than using quotes, it prefixes an x to the string to ensure it's not an empty string argument. Where it falls down of course is if there is a space in $SERVER.

jjinno · #3 11-02-2007

hahahaha... of course, the obvious answer escapes me.

I didn't even think of it as concatenation till you mentioned that.

Thank you

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