Scripting
#! /bin/sh # 已使用的 used=`free -m | awk 'NR==2' | awk '{print $3}'` # 空闲的 free=`free -m | awk 'NR==2' | awk '{print $4}'` echo "===========================" >> /home/mem/mem.log date >> /home/mem/mem.log echo "Memory usage before | [Use：${used}MB][Free：${free}MB]">> / Home / MEM / mem.log # 4g memory when idle or less, then clear the memory IF [$ Free -le 4096 ]; the then Sync && echo . 1 > / proc / SYS / VM / drop_caches Sync && echo 2 > / proc / SYS / VM / drop_caches Sync && echo . 3 > / proc / SYS / VM / drop_caches used_ok = ` Free -m | awk ' NR == 2 ' | awk ' {}. 3 Print $ ' ` free_ok = ` Free -m | awk 'NR==2' | awk '{print $4}'` echo "Memory usage after | [Use：${used_ok}MB][Free：${free_ok}MB]" >> /home/mem/mem.log echo "OK" >> /home/mem/mem.log else echo "Not required" >> /home/mem/mem.log fi exit 1
Add recurring task
crontab -e
Join (two in the morning to perform once a day)
1 2 * * * /home/mem/clearMemCache.sh
View timers
crontab -l
ps: time configuration instructions
43 21 * * * day 21: 43 execution 15 05 * * * day 05: 15 execution 0 17 * * * day 17: 00 execution 0 17 * * 1 every Monday 17 : 00 to perform 0 , 10 17 * * 0 , 2 , 3 every Sunday, Tuesday, Wednesday 17 : 11:00 and 17 : 10 to perform 0 - 10 17 1 * * from every 1 March 17 : 00-7: 10 every execution every 1 minutes 0 0 1 , 15 * 1 every January 1 and 15 and day 0 : 00 executed 42 4 1 * * each month 1 day 4 : 42 points execution 0 21 * * 1 - 6 from Monday to Saturday 21 : 00 execution 0 , 10 , 20 , 30 , 40 , 50 * * * * every 10 minutes executed * / 10 * * * * every 10 minutes execution * 1 * * * from 1: 0 to 1: 59 1 minute executed every 0 1 * * * 1 : 00 performs 0 * / 1 * * * every time executed every hour 0 0 * * * * every time executed every 1 hour 0 2 . 8 - 20 is / 3 * * * . 8 : 02 , . 11 : 02 , 14 : 02 , . 17 : 02 , 20 is : 02 performs 30 . 5 . 1 , 15 * and 15 * 1 May . 5 : 30 perform