You can look to use:
command -v <the_command>
There are also 2 other ways, that we will run through a little further down, but for now..
How to use the command if a conditional
if ! command -v <the_command> &> /dev/null
then
echo "<the_command> could not be found"
exit
fi
To summarize, there are 3 ways you can do this
Option 1 - Using command
command -v foo >/dev/null 2>&1 || { echo >&2 "foo is not installed. Aborting."; exit 1; }
Option 2 - Using type
type foo >/dev/null 2>&1 || { echo >&2 "foo is not installed. Aborting."; exit 1; }
Option 3 - Using hash
hash foo 2>/dev/null || { echo >&2 "foo is not installed. Aborting."; exit 1; }