How good are you at creating new cron jobs from memory?

Just a question I was curious about.

My full question:
Without referencing documentation or example crons of any kind, how easily could you create a new job for any given frequency?

Phooey on cron! I hope that I never have to touch a crontab again!

In my humble, "it's systemd to the rescue" here. I have vastly more options available to me when I use its timer facility.

In my humble, I think it is raining when a dog pees on my leg.

OT - My crontabs contain contain commented lines, easily adjusted to serve my purposes.

I pick what is CRon job, even though I know what it is. but I've never not once used it per se' . I have however created a script that I want ran once a week then just moved it into "cron.weekly" chmod +x scriptName -- done.

I just keep this at the top of my crontab file so I don't have to worry about remembering..

# minute (0-59) hour (0-23) day (1-31) month (1-12) day of week (0-6)

What "memory"?

I think I have CRS

It's second nature.

I do have a commented out block at the top of all of my crontabs just in case I space out though:

#
# Cron's default PATH:
#    /usr/bin:/bin
#
#   *  *  *  *  *  command to be executed
#   -  -  -  -  -
#   |  |  |  |  |
#   |  |  |  |  +----- day of week (0 - 6) (Sunday=0)
#   |  |  |  +------- month (1 - 12)
#   |  |  +--------- day of month (1 - 31)
#   |  +----------- hour (0 - 23)
#   +------------- min (0 - 59)

Originally Posted by orbea I just keep this at the top of my crontab file so I don't have to worry about remembering.. # minute (0-59) hour (0-23) day (1-31) month (1-12) day of week (0-6)

I like that. Thanks. (I used to look it up every time!)

man systemd? TL;dr -> Show me how to get sysd to do this

semiOnTopic, I've seen enuf threads about "my cronjob doesn't work", because of like path needed, quoting/gobbledygook needed cuz it's in crontab, etc., to scare me into "believing" cron might likely NOT work (for me)! LQsearch: Threads Titled cron* finds 1000!

Which leads me to be terrified of the "impossible" sysdMonster (ooops, lets NOT debate/discuss/mention sysd ... How did it get in this thread in the first place... Don't answer that: it will spoil my web search ending )

Edit: answer: OmyGosh, it's too late: it's already happened! The web is infested with such info, e.g. https://blog.higgsboson.tk/2013/06/0...n-replacement/ RIP cron; a new world order awaits my conquest!

p.s. Could you freely explain extra cost for CRS ram?
And I've decided to wait until sysd can properly read my mind, no matter how muddled it is.

Originally Posted by !!! semiOnTopic, I've seen enuf threads about "my cronjob doesn't work", because of like path needed, quoting/gobbledygook needed cuz it's in crontab, etc., to scare me into "believing" cron might likely NOT work (for me)! LQsearch: Threads Titled cron* finds 1000!

99.999% of crontab problems are from people who don't realize cron doesn't parse the system-wide or per-user shell setup scripts (.bashrc or similar) before executing, and therefore doesn't share all of the environment variables they're used to working with (most notably PATH). They also don't bother to redirect the output of their command to a log file, and then have no way of knowing what's wrong when it doesn't execute.

Two steps will eliminate basically all cron problems:
1) Run "export PATH=/usr/bin:/bin" before running the cron command interactively on your shell to see if it complains about any missing programs.
2) Add " >> $HOME/logfile 2>&1" to the end of your cron command when first adding it. If things aren't working right check ~/logfile to see what the output is, otherwise you can change the redirect to /dev/null to throw it away.

Thanks #10: I'm "cured" (of my "fear")! The very next post about cron that I ran into, was a path issue, and escaping the % in date (where cron takes % as a newline: WoW!). Now I believe "that's all there is to it"! Cool!

Love cron, my crontab is 80+ lines long, automation to the rescue. With lots of at for one-offs.
I also have a special pipe that runs in a dedicated term where my cronjobs output pertinent info for me.

Re post #7: actually that hdr is std on Centos 6 in /etc/crontab

Originally Posted by chrism01 Re post #7: actually that hdr is std on Centos 6 in /etc/crontab

I always wondered where I found it, that must be it!

I use the "Scheduled Tasks" gui but it still needs a little bit of thought.