If loop in the Korn Shell in HP Ia 64

[CA1490051]

Hi all,

I am trying to write a small shell script in HP UX Ia64.

read Option

if [ $option == 1 ]; then
echo One
else
echo Two
fi

But, it says
== unknown test operator

But i think we should use == for korn and
if ( $Option eq 1 )
for csh and tcsh.

Can any one Please Correct me where i am going wrong.

thanks in advance
Vikram

[Ivan Krastev · Accepted solution]

For compare use '=', not '=='. See more - http://www.well.ox.ac.uk/~johnb/comp/unix/ksh.html#comparisons


regards,
ivan

[Duncan Edmonstone]

Vikram,

Try double square braces:

if [[ $option == 1 ]]; then
echo One
else
echo Two
fi


HTH

Duncan

[James R. Ferguson]

Hi Vikram:

The manpages for 'test(1)' will guide you.

Remember, if you are using '/usr/bin/sh' as your script interpreter, then you are using the HP-UX POSIX shell --- a superset of the Korn88 provided in '/usr/bin/ksh' by HP.

Regards!

...JRF...

[CA1490051]

Hi All,

thank you very much for the reply.

Ivan's solution is working fine for me.
Also before closing the thread i request Ivan to send the similar links for Tcsh and csch shell scripting if they are existing .

I tried going back in the present link but it seems only ksh and awk scripting is present in the link.

thanks and regards
Vikram

[Ivan Krastev]

Use google - there are too many similar how-to's.

regards,
ivan

[Peter Nikitka]

Hi,

use the variable reference in double quotes - so there will be no syntax error, when it is completely unset:
if [ "$option" = 1 ]
then
...

Same construct for tcsh/csh:
if ("$option" == 1) then
echo One
else
echo NOT-One
endif

mfG Peter

[Bill Hassell]

And for completeness, testing using = is for strings which may or may not contain non-numeric values. For pure numbers, use -eq as in:

if [ $option -eq 1 ]; then
echo One
else
echo Two
fi

I prefer to use -eq (and relatives like -ne -gt -le ...) for numbers even though some string comparisons will work. The problem with string compares is that they won't check invalid numbers and magnitude comparisons such as > or < can have unexpected results.

For simple actions, you can simplify the test to a one-liner like this:

[ $option -eq 1 ] && echo One || echo Two

The man page for ksh is helpful here.

[James R. Ferguson]

Hi (again):

If you have found a solution, please assign points and close this thread. Thanks!

http://forums1.itrc.hp.com/service/forums/helptips.do?#28

Regards!

...JRF...

[Pete Randall]

OK - who are you and what have you done with the real Jim Ferguson????


Pete