UNIX for Dummies Questions & Answers

Folks,
how to trigger a shell script eg " B " from shell script eg "A" and parse different arguments to the child shell script "B" - like 0 the first time the shell script "B" is triggered and 1 the next time.


Shell script A -----------> launch shell script B with an args 0 --------> done

The next time Shell Script A is launched--------------> Launch shell script B with an args 1 -----------------------> done


Thanks for your help

Ven

You can save the argument which is being passed to script B in a file everytime script A gets executed.

Here is an example.

Code:

 
Script A
 
LOC="Where you want to save the argument counter file"
ARG_CNT_FILE="Name of file"
if [ ! -f ${LOC}/${ARG_CNT_FILE} ] ## Checking for the existance of FILE
then
ARG_CNT=0 ## since the FILE doesn't exist, hence 1st time execution
else
ARG_CNT=`cat ${LOC}/${ARG_CNT_FILE}` ## FILE exists get the argument value from the FILE
ARG_CNT=`expr ${ARG_CNT} + 1` ## Increment the counter by 1
fi
echo ${ARG_CNT} > ${LOC}/${ARG_CNT_FILE} ## Save the new value of counter to the FILE
SCRIPT_B ${ARG_CNT} ## Execute script B with the argument

Regards,
Vishal

Hello Vishal,
Thanks for you reply , i have one more question that i think you can answer, how to detect if the script B is running and stop the script B immediately in the middle and exit out of the program.

Thank you
venu

What does it do? How will it be launched (script A ...) batch/in background?

Script B runs when script A is triggered, and if you want to put the stopping feature in the code then you need to first decide the condition when you want to stop B.

If you can think of such condition then it will be easy.

Regards,
Vishal

Script A is launched by Task scheduler on windows.

Once script A is launched, it will write a 0 in to the args file, and parse the 0 to the script B, script B detects that it received an yes flag to go ahead and do whatever it wants to do.

else
if script B receives an argument of 1 and has already been executing then it should stop doing what ever it is doing and quit or if it is starting a fresh cycle to execute then it should stop and quit as it is

Basically i need something like a switch to stop the script B from executing again if it has been already executed once.
or if scriptB is in process of process of doing what it is supposed to then i want it to stop as it is at that point and exit out of the program.


Thanks to Vishal and VBE for their valuable suggestions

Venu

after passing argument 1 to the file , how about getting the pid and killing the script B

i am not sure whether this works as you are specifying windows system but its possible to get the pid and for any process running using

Code:

ps -ef | grep "scriptb"

later taking the $2 using awk and passing kill can stop the script b