add cron tips

add del_logs.sh

README.md

@@ -106,4 +106,14 @@ sudo systemctl status <service>.service
 sudo systemctl enable <service>.service
 ```
 
+### Cron
+
+```crontab -e```
+
+```0 0 1 1 * command.sh``` - Every year in 1 January 00:00:00 \
+```*/1 * * * * command.sh``` - Every minute\
+```0 */3 * * 2,5 command.sh``` - One time per 3 hours in Tue and Fri\
+```0 0,12 1 */2 * command.sh``` - At minute 0 past hour 0 and 12 on day-of-month 1 in every 2nd month
+
+
 <h1 align="center"><a href="#top">▲</a></h1>

functions/del_logs.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/bash
+
+# removes log files with size greater then 100Mb
+
+for i in $(sudo du -a /var/log/* | sort -hr | tr '\t' ':')
+do
+
+    size_file=( $(echo "$i" | tr ':' ' ') )
+
+    size="${size_file[0]}"
+    file="${size_file[1]}"
+
+    if [ "$size" -ge 102400 ] && [ -f "$file" ]; then
+        sudo rm "$file"
+    fi
+
+done