Simpler Navigation for Servers and Operating Systems - Please Update Your Bookmarks
Completed: a much simpler Servers and Operating Systems section of the Community. We combined many of the older boards, so you won't have to click through so many levels to get at the information you need. Check the consolidated boards here as many sub-forums are now single boards.
If you have bookmarked forums or discussion boards in Servers and Operating Systems, we suggest you check and update them as needed.
Languages and Scripting
Showing results for 
Search instead for 
Did you mean: 

Environment Variable Count

Go to solution
Pascal Kouknas
Occasional Contributor

Environment Variable Count

Hi all,
What I am trying to do is set an environment variable.
This variable will change when the user runs a specific report.
run no 1 SEQ=20001
run no 2 SEQ=20002

What I want to do is retain this new value so as next time the user logs on the sequence continues



P.S. This thread has been moved from HP-UX > General to HP-UX > languages - HP Forums Moderator

Patrick Wallek
Honored Contributor

Re: Environment Variable Count

The easiest way to do this would be to have a file somewhere that gets looked when the user logs in and / or runs the report.

# cat /dir/SEQ

# export SEQ=`cat /dir/SEQ`
# echo $SEQ

Then when you increment SEQ you do a:

echo $SEQ > /dir/SEQ

and the new value will then be kept in the file for the next run.
David Totsch
Valued Contributor

Re: Environment Variable Count


Patrick's is good if you are keeping the sequence per user (only one copy of the script running at a time will update the file that records the sequence number). If that is not true, you will need to come up with a solution that is better than "the last person to write the file wins".

If so, here are two suggestions: 1) use a directory and touch a file with the sequence number in the name (be careful of how ls(1) lists numbered file names -- not necessairly in numerical order), get the last file in the list, increment the number and touch the file name (only if it does not already exist). 2) use a single file, get the last number off the bottom, increment it, append it to the file, and make sure it is not a duplicate (unfortunately, I ran out of ideas on how to deal with a duplicate -- sigh). 3) If you run your sequencing script as an LP spool script, you could use the job number...

Christophe MAILHE
Frequent Advisor

Re: Environment Variable Count

Hi Pascal,

In order to make sure not to have duplicate you could use the following method :

while :
mkdir /tmp/get_new_seq 1>/dev/null 2>/dev/null
if [ $? = 0 ]
export SEQ=`cat /dir/sequence_number`
echo $NEXTSEQ > /dir/sequence_number
rmdir /tmp/get_new_seq 1>/dev/null 2>/dev/null

As the loop will continue until the directory is created, 2 users could not read /dir/sequence_number at the same time.

Hope that will help.