While condition in shell script

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1

while [ "$driverName" = "" -o `checkFile "$driverName"` = "NOK" ]
do
if [ "$driverName" = "" ];then
read driverName
else
driverName=""
fi
done

can anyone please explain what exactly is happening on 1st line...is it like the conditions being ORed...I have no clue about this.

2

You are right.

Boolean operator: -o is logical OR. If one of the operands is true then condition would be true.

There are other Boolean operators:

-a for logical AND and ! for logical negation.

3

Thanks for confirming...could you be kind enough to tell me what the condition is doing...i have no idea about shell script...i just need to understand this script..that is the problem

while [ "$driverName" = "" -o `checkFile "$driverName"` = "NOK" ]

i think driverName variable is null OR then i could not understand wht is tht checkfile and NOK...Could you pls help

4

First operand is checking if string value: $driverName is equal to NULL ""

Second operand appears to be calling a function: checkFile by passing string value: $driverName as argument and checking if the return value is equal to "NOK"

5

You are spot on brother...yes there is a function checkFile...Really thanks for the quick help....