Let us use the power of Bash here, ${my_variable^^} (the carrot symbol, two times)
Example of changing the case from lower to upper:
[email protected]:~$ my_variable=codetryout
[email protected]:~$
[email protected]:~$ echo $my_variable
codetryout
[email protected]:~$
[email protected]:~$ echo ${my_variable^^}
CODETRYOUT
This is very useful, for example when you want to process any user input, regardless of its case.
# Entering all lowercase - yes
[email protected]:~$ read userinput
yes
[email protected]:~$ [[ ${userinput^^} == YES ]] && echo YES
YES
# Entering Yes, in mixed case - Yes
[email protected]:~$ read userinput
Yes
[email protected]:~$ [[ ${userinput^^} == YES ]] && echo YES
YES
# Entering all in uppercase - YES
[email protected]:~$ read userinput
YES
[email protected]:~$ [[ ${userinput^^} == YES ]] && echo YES
YES