You would use the crontab
utility to set both up:
is how you do that (as "you"). The -e
"edit crontab for user."
Now, what the heck do you do, eh?
If you look at the manual page for crontab
there are examples that may prove useful. What you want to do is execute a command at 20 hours on Friday then execute another command at 21 hours on Friday which would look something like this
0 20 * * fri command
0 21 * * fri command
Now, in the above, command
can be a shell program (rather than the long lines you have above); what you could do is save your first command line as a shell program named, oh, say, startit
and that other as, what the heck, stopit
and that might make things easier for you to keep track of (and if you ever have to edit either one...).
The fields in crontab
MIN HOUR DAY MONTH DAY_OF_WEEK Command
Minutes are 0-59, hours are 0-23, Day is the day of the month, Day of the week is the three-character abbreviation, and Command is what to execute. Be sure to peruse the manual page for more details and examples.
Note that you really do need to look at the manual page for your distribution -- crontab
varies from system-to-system and may not be identical on all.
Hope this helps some.