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Logical expression in POSIX compliant Korn Shell


 
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# 1  
Old 02-28-2012
Logical expression in POSIX compliant Korn Shell

Hi,
i want to check if a variable var1 is not a or b or c
pseudo code:
If NOT (var1 = a or var1 = b or var1 = c)
then
...
fi

I want to use POSIX complaint Korn shell, and for string comparison
For the following code, logical.sh
Code:
#!/usr/bin/ksh
var="j"
echo "Var : $var"

if ! { [ "$var" = a ] || [ "$var" = b ] || [ "$var" = b ] ;}
then    
   echo "var not in the list"
else    
   echo "var in the list"
fi

var="b"
echo "Var : $var"

if ! { [ "$var" = a ] || [ "$var" = b ] || [ "$var" = b ] ;}
then    
   echo "var not in the list"
else    
   echo "var in the list"
fi

I gave execute permissions to the script, however it only seems to run good when run by 'sh ' and not by the script itself.
We run all our jobs without specifying 'sh ' ahead

$ chmod 777 logical.sh
$ logical.sh
Var : j
./logical.sh[3]: syntax error at line 6 : `}' unexpected
$ sh logical.sh
Var : j
var not in the list
Var : b
var in the list
$

Where am i going wrong?
Is it necessary to enclose the variable in double quotes but not the literals on the other side of comparison operator?

Thanks,
-srinivas yelamanchili
# 2  
Old 02-28-2012
Invert the logic so you don't need that ! in front.

Code:
if [ "$var" != "a" ] && [ "$var" != "b" ] && [ "$var" != "c" ]
then
...
fi

# 3  
Old 02-29-2012
Your shell may not be POSIX compliant. What ksh are you using? pdksh? On what system?
# 4  
Old 02-29-2012
The box is HP-UX 11.11

Code:
echo $SHELL

Version M-11/16/88f

$
Code:
whereis ksh

ksh: /usr/bin/ksh /usr/dt/man/man1/ksh.1 /usr/dt/share/man/man1/ksh.1 /usr/share/man/man1.Z/ksh.1

$
Code:
 ksh

Version 11/16/88

What's the latest recommended version of Korn shell (and POSIX compliant) that I can use?

Thanks,
-srinivas yelamanchili
# 5  
Old 02-29-2012
Kornshell 88 is not 100% POSIX compliant

Try to run it as sh:
Code:
#!/usr/bin/sh

# (I think it is in /usr/bin or was it #!/bin/posix/sh ??)
It will still use ksh, but it should emulate a POSIX shell...
(See man sh-posix)

---------- Post updated at 09:49 ---------- Previous update was at 09:27 ----------

I forgot, there is usually also a POSIX compliant ksh93 on HPUX:
Code:
/usr/dt/bin/dtksh

This User Gave Thanks to Scrutinizer For This Post:
# 6  
Old 02-29-2012
Thanks Scrutinizer, the dtksh helped !!!

-srinivas
# 7  
Old 02-29-2012
Good, out of interest, did you happen to try the posix shell? Did that work?

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