Variable comparison

Shell Programming and Scripting
1

Can anyone help me with this section of code?

The scenario is a value drops from A to B or A to C or B to C.
If it drops from A to B or B to C, we print "Drop one level"
If it drops from A to C, we print "Dropped two levels".

The problem is script is throwing error when comparing variable values.

A test script is shown below:

# var1=A  
# var2=B
# var3=C
# if [ $var1 = "A" && $var2 = "B" ] || [ $var2 = "B" && $var3 = "C" ];
> then
> echo "Down one level"
> fi
ksh: test: ] missing
ksh: test: ] missing

If I remove the last comparison after the "||" sign the script works!

I have tried troubleshooting, but not getting it right.
Can anyone help me?

2

use two brackets or use the proper operators for test. man test for details

if [ $var1 = "A" -a $var2 = "B" ] || [ $var2 = "B" -a $var3 = "C" ]
then
   echo "Down one level"
fi

if [[ $var1 = "A" && $var2 = "B" ]] || [[ $var2 = "B" && $var3 = "C" ]]
then
   echo "Down one level"
fi

and the optimized version

if [ $var2 = "B" ] && [ $var1 = "A" -o $var3 = "C" ]
then
   echo "Down one level"
fi
3

All three suggested code works! Thanks a lot Mr. Frank.