From 34ee9055eb8da073b90836e3e5012b1378460113 Mon Sep 17 00:00:00 2001
From: Malin Freeborn <malinfreeborn@posteo.net>
Date: Wed, 23 Nov 2022 21:36:47 +0100
Subject: [PATCH] fix crontabe

---
 basics/cron.md   | 89 +++++++++++++++++++++++++++++++++++++++---------
 system/cronie.md | 33 ------------------
 2 files changed, 72 insertions(+), 50 deletions(-)
 delete mode 100644 system/cronie.md

diff --git a/basics/cron.md b/basics/cron.md
index f66406a..816dc81 100644
--- a/basics/cron.md
+++ b/basics/cron.md
@@ -4,32 +4,26 @@ tags: [ "Documentation", "Basics" ]
 ---
 # Cron
 
-Various services from cron exist, e.g.
+The crontab program might have various names, like `cronie` or `crond`.
 
-> sudo apt -y install cron
+> sudo apt search -n ^cron
 
-Start the cronie with
+Once installed, search for the service name, and start it.
+
+> sudo systemctl list-unit-files | grep cron
 
 > sudo systemctl enable --now cron
 
-Specify a cron job with:
+You can *e*dit your crontab with:
 
-> cron -e
+> crontab -e
 
-You can run a script with:
 
-*/10 * * * * /home/pi/script.sh
+```
 
-... which would run every 10 minutes.
-
-To run something as root, do:
-
-> sudo crontab -e
-
-For example, you can update the database, meaning searches with 'locate' command will be faster.
-
-> */30 * * * * /usr/bin/updatedb
+39 */3 * * * /usr/bin/updatedb
 
+```
 ## Syntax
 
 `* * * * *`
@@ -49,9 +43,70 @@ Doing the same thing, but only in February, would be:
 
 `0 15 * 2 7`
 
-# Testing with runparts
+### Full Paths
+
+Executing something requires the full path to where it is, so you cannot simply use `apt update -y`, because cron does not know where `apt` is.
+Instead, find out where it is:
+
+> type -P apt
+
+`/usr/bin/apt`
+
+Then put that into the crontab:
+
+> sudo crontab -e
+
+`40 */3 * * * /usr/bin/apt update -y`
+
+This will run `apt update -y` as root every 3 hours, at 40 minutes past the hour, e.g. 00:40, 03:40, 06:40.
+
+## Directories
+
+You can execute a script as root by putting it into a directory, instead of in the tab.
+Look at the available cron directories:
+
+> ls /etc/cron.\*
+
+### Testing with runparts
 
 Run-parts runs all executable scripts in a directory.
 
 > run-parts /etc/cron.hourly
 
+## Tips
+
+### Variables
+
+Add your `$HOME` to crontab to use scripts.
+First add `HOME=/home/user`, then you can use syntax like this:
+
+0 * * * * $HOME/.scripts/myScript.sh
+
+*Remember to test the script by executing that line first*:
+
+> $HOME/.scripts/myScript.sh
+
+You can also add your regular path to your crontab as a variable (see example below).
+If you're using vim as the editor, just run this at the top of your crontab:
+
+> :r!echo $PATH
+
+### Location
+
+The crontab files are in `/var/spool/cron/`, so you can backup or restore them.
+
+# Example
+
+```
+HOME=/home/user
+PATH=/usr/condabin:/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/home/user/.local/bin:/home/user/.scripts/:/home/user/.local/bin:/home/user/.scripts/
+
+1 0 1 * *    /usr/bin/mkdir -p $HOME/arc/$(date +%Y/%m)
+
+18 0 1 */3 * $HOME/.scripts/mail-clean.sh
+
+* * * * * ping -c 1 home || mail-pull.sh
+
+50 18 * * * /usr/bin/timeout 30m /usr/bin/syncthing
+
+```
diff --git a/system/cronie.md b/system/cronie.md
deleted file mode 100644
index 49a2f16..0000000
--- a/system/cronie.md
+++ /dev/null
@@ -1,33 +0,0 @@
----
-title: "cronie"
-tags: [ "Documentation", "System" ]
----
-
-Various services from cron exist, e.g.
-
-> sudo apt -y install cronie
-
-start the cronie with
-
-> sudo Systemctl start cronie
-
-start a cron with 
-
-> cron -e
-
-You can run a script with:
-
-*/10 * * * * /home/pi/script.sh
-
-... which would run every 10 minutes.
-
-To run something as root, do:
-
-> sudo crontab -e
-
-For example, you can update the database, meaning searches with 'locate' command will be faster.
-
-> */30 * * * * /usr/bin/updatedb
-
-
-