I have a bash script (like A.sh) which includes a variable like:
ToBeRead=$(sed -n '$=' LogFile)
I was wondering how can I use this variable in a makefile which is called from A.sh like:
make -f Makefile SayHello
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2 Answers
You can explicitly set make variables:
make ToBeRead:="$(sed -n '$=' Logfile)" SayHello
Comments
Forgive me if this is a dumb noob answer, but couldn't you use an environment variable?
In A.sh:
export VARIABLE=value
In makefile:
# sets VARIABLE if not already set
VARIABLE?=other_value
I could be wrong I'm new to makefiles as well.
4 Comments
user3684042
Actually tried this one, but seems variables' life time is limited to the execution of script, unless you make them permanent.
Will
Ah, I see. So this is a dumb noob answer ;)
MadScientist
The A.sh script invokes make and make inherits a copy of the exported environment from its parent. Regardless of when A.sh exits (although in your case here it won't exit until after make exits anyway), make still has this copy. I expect that the mistake the questioner made was not exporting the variable. If the variable is not exported, then it's not copied to child programs. So no, @Will, this is not a dumb noob answer: it will work as you've described it here.
Will
Thanks for the clarification @MadScientist, very helpful. The export keyword is something I've only used once or twice.