Setting global variables with BASH/Linux

UNIX for Advanced & Expert Users
1

I am using functions in a script and for some strange reason the EXPORT command doesnt seem to be making my variables global.

Anyone got any ideas?

I am using one function to pass some output top another using the pipe command, eg

Function 1 | Function 2

Function 2 reads the value passed from Function one and sets some variables based on its value then exports them

setStartSeq() {
read logFile
echo "Start redo log: $logFile"
arcPrefix=$(echo $logFile | cut -d_ -f1)""$(echo $logFile | cut -d -f2)
startSeq=$(echo $logFile | cut -d_ -f3 | cut -d. -f1)
export arcPrefix=$arcPrefix
export startSeq=$startSeq
}

Yet later on in the script another function tries to use the above exported variables and they arent set!!

I have confirmed that by running an export -p in the later function and all values set above are blank.

I am new to BASH and Linux but have used export without issue with kornshell.

Any help would be greatly appreciated :slight_smile:

2

i assume the functions are running in a subshell depending on how you ionvoke them.
The subshell is closed after execution an the variables are lost. export does only work from parent to child.

3

Yes it does, but I dont know how else to do it.

I have a function that extracts data from a database, which another function reads. This stores a starting sequence number.

Then the script performs various actions.

Then at the end another function needs to get the starting sequence number to process some files.

Here are the functions and how they are called. The first two pipelined are the ones extracting/reading the data from within the database, then the bottom one needs to get the value read by setStopSeq

getLogFile | setStopSeq
copyArc

4

You shouldn't have to use export to make variables within a function become global. Once a function is run, it's variables should be available throughout the rest of your script.

If you are invoking a subshell (while statement?) in one of your functions, that's another story. It would help to see the other functions to debug this problem.

Are you certain that the values from Function 1 are being passed to Function 2 when using the pipe? If you want to pass a variable to your second function, I'd do it like this:

func1 () {
var1=1
}

func2 () {
var2=$1
}

func1
func2 $var1

echo $var2