topic Re: Error with script to compare two text strings in Operating System - HP-UX

Error with script to compare two text strings

Preet Dhillon — Thu, 29 Nov 2001 11:04:45 GMT

Dear Colleagues,

The script below tests to see if the value of the MONTH variable is "Jan". If so, it sets another variable called MON to 01 :
MONTH="Nov"
if test $MONTH="Jan"
then
MON=01
else MON=UNKNOWN
fi
echo "Month is $MONTH"
echo "Mon is $MON"

When I run this, I get :
Month is Nov
Mon is 01

I was expecting the value of Mon to be UNKNOWN but instead it is 01. In other words, the test condition in my if-statement is not working.
Does anyone know where this is going wrong?

Many thanks and regards,
Preet :-)

Re: Error with script to compare two text strings

Kevin Bingham — Thu, 29 Nov 2001 11:15:13 GMT

Hi Preet,

Try this

MONTH=`date|cut -d " " -f 2`
if [ $MONTH = "Jan" ]; then
MON=01
else MON=UNKNOWN
fi
echo "Month is $MONTH"
echo "Mon is $MON"

Re: Error with script to compare two text strings

Duncan Edmonstone — Thu, 29 Nov 2001 11:18:23 GMT

The shell needs white space between operators to recognise them...

Change

if test $MONTH="Jan"

to

if test $MONTH = "Jan"

HTH

Duncan

Re: Error with script to compare two text strings

Santosh Nair_1 — Thu, 29 Nov 2001 11:21:27 GMT

Try putting a space around the equal size in the test statement, i.e.:

MONTH="Nov"
if test $MONTH = "Jan"
then
MON=01
else MON=UNKNOWN
fi
echo "Month is $MONTH"
echo "Mon is $MON"

Notice the space before and after the = in the 'if test' statement.

Hope this helps.

-Santosh

Re: Error with script to compare two text strings

Phil Daws_1 — Thu, 29 Nov 2001 12:18:45 GMT

Use the following and cut the code down aswell ;)

MONTH="Nov"
MON=UNKNOWN
[ $MONTH = "Jan" ] && MON=01

Re: Error with script to compare two text strings

Andreas Voss — Thu, 29 Nov 2001 14:12:25 GMT

Hi,

you can also use a case construct:

case $MONTH in
Jan) MON=01;;
Feb) MON=02;;
Mar) MON=03;;
Apr) MON=04;;
May) MON=05;;
Jun) MON=06;;
Jul) MON=07;;
Aug) MON=08;;
Sep) MON=09;;
Oct) MON=10;;
Nov) MON=11;;
Dec) MON=12;;
*) MON=UNKNOWN;;
esac

Regards

Re: Error with script to compare two text strings

Wodisch — Thu, 29 Nov 2001 14:38:55 GMT

Hello Preet,

the reason is the missing spaces, as all the others already told you...
But as an additional tip:
ALWAYS quote substitutions, e.g.

if [ "$MONTH" = "Jan" ]
...
case "$MAONTH" in
...

for the simple reason that one day your variable might be unset or plain empty and then you will get an syntax error message from the shell - but with quotes your script will still work.

Just my ???0.02,
Wodisch