How to compare time in shell script?

Question

I have two time variables. I want to compare it in if statement in shell script.

e.g. time1=HH:MM:SS and time2=HH:MM:SS.

Format is HH:MM:SS.

if [it matched]
then
    echo "matched" 
else
    echo "not matched"
fi

Answer 1

If you want to compare the (contents of) two variables to a particular HH:MM:SS string, then just compare them to those strings and tie the tests together with a logical "and" (&&):

if [ "$time1" = "01:23:45" ] && [ "$time2" = "01:42:42" ]
then
  echo matched
else
  echo not matched
fi

Another option is to use case; it allows for some flexibility in matching the times, in case you don't want to match against a specific HH:MM:SS. To start with, let's tie the two times together with an implicit "and":

time1=01:23:45
time2=01:42:42
case "$time1,$time2" in
  (01:23:45,01:42:42) echo yes;;
esac

Here I stubbed in a comma, just to help you the script-reader see what's going on; it could be omitted.

Now let's say that you don't care as much about time2's SS portion:

case "$time1,$time2" in
  (01:23:45,01:42:*) echo yes;;
esac

Or maybe you want time2's seconds to be in a certain range:

case "$time1,$time2" in
  (01:23:45,01:42:4[1-3]) echo yes;;
esac

You can extend the examples from there.

Answer 2

If the format is the same, just compare them like any other string:

$ [ "$time1" = "$time2" ] && echo "match" || echo "no match"