Dynamically construct variables inside the script and fetch values from source parameters

Question

I have a txt file extract.dat which is read inside my code using source.

$ cat extract.dat
ExchgRate_prop="EDB_NAME=share_exchange SRC_WDS=wds PN=ExchgRate"
Compliance_prop="EDB_NAME=share_compliance SRC_WDS=wca PN=com"
Unitcost_prop=="EDB_NAME=share_unitcost SRC_WDS=wda PN=unit"

source ./ extract.dat

now I would have got all the varaibles inside my code. if my code takes an argument $PROJ with value as 'ExchgRate' , how can i concatenate "$PROJ""_prop" to create the variable ExchgRate_prop and then get value "EDB_NAME=share_exchange SRC_WDS=wds PN=ExchgRate"

Answer 1

You can use bash variable indirection. Ex. given

$ echo "$ExchgRate_prop" 
EDB_NAME=share_exchange SRC_WDS=wds PN=ExchgRate

and

$ PROJ=ExchgRate

then

$ var=${PROJ}_prop
$ echo "${!var}"
EDB_NAME=share_exchange SRC_WDS=wds PN=ExchgRate