topic Re: trouble with "||" operand in Operating System - HP-UX

trouble with "||" operand

lawrenzo_1 — Thu, 17 Apr 2008 10:09:30 GMT

Hi all,

I cant get my if statement to work and I believe it may be to do with the || in the script:

print "Please enter a hdisk or vpath you would like to check and potentially remove: \c"

while true
do

read ANS

if [[ $ANS != hdisk[0-9]* || $ANS != vpath[0-9]* ]] ; then

print "incorrect selection please enter a valid hdisk or vpath: \c"

else

break

fi
done

what is wrong here?

is it to do with [[

 ]] - should I be using [ 
many thanks

Chris.

Re: trouble with "||" operand

OFC_EDM — Thu, 17 Apr 2008 10:15:53 GMT

if [[ $ANS != hdisk[0-9]* || $ANS != vpath[0-9]* ]]

wouldn't it be

if [[ $ANS != hdisk[0-9]* ] || [ $ANS != vpath[0-9]* ]]

Re: trouble with "||" operand

lawrenzo_1 — Thu, 17 Apr 2008 10:27:57 GMT

no that is not correct ...

Please enter a hdisk or vpath you would like to check and potentially remove: ./check_disk.ksh[5]: 0403-057 Syntax error at line 12 : `]' is not expected.

Re: trouble with "||" operand

piyush mathiya — Thu, 17 Apr 2008 10:40:41 GMT

No man you have to use -a (And) or -o (OR) operator instad of "||"

Regards,
Piyush Mathiya

Re: trouble with "||" operand

Dennis Handly — Thu, 17 Apr 2008 11:00:46 GMT

You have the wrong operator. You need:
if [[ $ANS != hdisk[0-9]* && $ANS != vpath[0-9]* ]]; then

Yours will always be true.
You may want to reverse your condition so it is more obvious:
if [[ $ANS = hdisk[0-9]* || $ANS = vpath[0-9]* ]] ; then
break
fi

Note your pattern matching will match hdisk, followed by 0 .. 9, followed by anything.

>Piyush: you have to use -a (And) or -o (OR) operator instead of "||"

No, [[ ]] supports && and ||. [] only supports -a and -o.

Re: trouble with "||" operand

Oviwan — Thu, 17 Apr 2008 11:01:30 GMT

hey

try it with quotes:

if [[ "$ANS" != "hdisk[0-9]*" || "$ANS" != "vpath[0-9]*" ]] then

regards

Re: trouble with "||" operand

Dennis Handly — Thu, 17 Apr 2008 11:03:52 GMT

>is it to do with [[ ]] - should I be using [ ] for testing a pattern?

Only [[ ]] does pattern matching, [ ] does exact match.

>Oviwan: try it with quotes:
if [[ "$ANS" != "hdisk[0-9]*" || "$ANS" != "vpath[0-9]*" ]]

No, that will break pattern matching.

Re: trouble with "||" operand

piyush mathiya — Thu, 17 Apr 2008 11:15:41 GMT

Hi dear,
As I already post a solution, you can use the following command.

if [[ $ANS != hdisk[0-9]* -a $ANS != vpath[0-9]* ]] ; then

Regards,
Piyush Mathiya

Re: trouble with "||" operand

OFC_EDM — Thu, 17 Apr 2008 11:21:45 GMT

Which shell are you using?

Re: trouble with "||" operand

Aashique — Thu, 17 Apr 2008 11:23:38 GMT

Hi,
your pattern hdisk[0-9]* will not work in if condition.

print "Please enter a hdisk or vpath you would like to check and potentially remove: \c"

while true
do

read ANS
a=`echo $ANS|awk '/hdisk[0-9]/ {print $0}'`
b=`echo $ANS|awk '/vpath[0-9]/ {print $0}'`

if [ $a ] || [ $b ] ;
then

print "incorrect selection please enter a valid hdisk or vpath: \c"

else

break

fi
done

thanks & regards

aashique

Re: trouble with "||" operand

Dennis Handly — Thu, 17 Apr 2008 11:28:54 GMT

>O'Kevin: Which shell are you using?

Chris is obviously using a real shell and not the scummy C shell.

>Aashique: your pattern hdisk[0-9]* will not work in if condition.

Why not? Pattern matching will work in [[ ]].

Re: trouble with "||" operand

Aashique — Thu, 17 Apr 2008 11:35:21 GMT

Hi,
I check this way and its running.
$ more test
ANS=vpath02
a=`echo $ANS|awk '/hdisk[0-9]/ {print $0}'`
b=`echo $ANS|awk '/vpath[0-9]/ {print $0}'`

if [ $a ] || [ $b ]
then
echo " YES"
else
echo "NO"
fi
$ ./test
YES

Re: trouble with "||" operand

lawrenzo_1 — Thu, 17 Apr 2008 11:39:18 GMT

just back from lunch

Ok thanks all,

I'll give take a look at these suggestions and let you know ...

Re: trouble with "||" operand

lawrenzo_1 — Thu, 17 Apr 2008 11:48:49 GMT

thanks all for the help and suggestions - Dennis gave the best solution for the korn shell!

#!/bin/ksh

print "Please enter a hdisk or vpath you would like to check and potentially remove: \c"

while true
do

read ANS

if [[ $ANS = hdisk[0-9]* || $ANS = vpath[0-9]* ]] ; then

break
print "incorrect selection please enter a valid hdisk or vpath: \c"

else

print "incorrect selection please enter a valid hdisk or vpath: \c"

fi
done

echo $ANS

Re: trouble with "||" operand

Yogeeraj_1 — Thu, 17 Apr 2008 12:01:10 GMT

hi chris,

have a look the following url:
http://www.injunea.demon.co.uk/pages/page205.htm

should look something like:
if [ $ANS != hdisk[0-9]* ] || [ $ANS != vpath[0-9]* ]
then
..

(unfortunately, i do not have any machine at hand to validate this right now!)

The [[ ]] are not properly stated.

hope this helps!

kind regards
yogeeraj

Re: trouble with "||" operand

Dennis Handly — Thu, 17 Apr 2008 18:31:41 GMT

>Yogeeraj: have a look the following URL:
http://www.injunea.demon.co.uk/pages/page205.htm

This appears to be Borne shell document, not ksh or posix.
http://docs.hp.com/en/B2355-60130/sh-posix.1.html
http://docs.hp.com/en/B2355-60130/ksh.1.html