[SOLVED] if condition error: integer expression expected

Kashif_Bash · 04-17-2012, 06:10 PM

I am trying to run following condition with both variables having numeric values "1,2,3"

Code:

if [ '$NEW_STATE' -gt '$OLD_STATE' ];

when i run it i get following error:

Code:

$NEW_STATE: integer expression expected

Please correct me where I'm doing wrong.

I'm trying to check either New State is greater or Old state.

jlinkels · 04-17-2012, 06:35 PM

'$NEW_STATE' is interpreted literally as the string $NEW_STATE. Use double quotes: "$NEW_STATE". See the debugging tip in my signature.

jlinkels

grail · 04-18-2012, 02:41 AM

Also, if using bash I would recommend using (()) instead of [], mainly for readability:

Code:

if (( NEW_STATE > OLD_STATE ))

pan64 · 04-18-2012, 04:03 AM

-gt is used to compare numbers, > or < are used to compare strings.

pan64 · 04-18-2012, 04:06 AM

also '$NEW_STATE' will not be evaluated because of ', you should use " instead (or nothing, but I prefer to use ").
So you should write:

Code:

if (( "$NEW_STATE" -gt "$OLD_STATE" ));

if you are really sure, those variables contain integers.

grail · 04-18-2012, 05:25 AM

@pan64 - May I suggest you confirm your facts before commenting. Whilst you are correct that when using [] or [[]] that the symbols and switches are as you have stated in post #4,
this is not the case when using (()). Also, when inside this construct you are not required to use the $ for variable expansion.

Please see the below link if you would like to learn more:

http://mywiki.wooledge.org/ArithmeticExpression

pan64 · 04-18-2012, 05:37 AM

Quote:

Originally Posted by grail

@pan64 - May I suggest you confirm your facts before commenting. Whilst you are correct that when using [] or [[]] that the symbols and switches are as you have stated in post #4,
this is not the case when using (()). Also, when inside this construct you are not required to use the $ for variable expansion.

Please see the below link if you would like to learn more:

http://mywiki.wooledge.org/ArithmeticExpression

thanks for correcting.