I am trying to write a bash script that takes in a users input of a specific date in a format such as MM/DD/YYYY and returns whether or not that specific date was during daylight savings time or not. Is there a specific function that checks this? Does the date command have a way to do this? I am using RHEL 6.4.
I don't have access to a Linux system (so the following is untested), but the following should give you the Timezone string that applies to midnight at the start of the given date:
test_date="12/25/2000" # Format is "MM/DD/YYYY"
date -d"$test_date" +%Z
Note that on dates when there is a switch to or from daylight savings time, the answer for those two days each year (in areas where daylight savings time is observed) is not a constant for the entire day. That is why it is important to specify a specific time for the test rather than assume that the answer applies to the entire day.