1. Delete 0 byte file
Find -size 0 -type -exec RM -rf F {} \;
2. Check process
according to descending order of memory
PS -e -o "% C:% p:% z:% a "| Sort -k5 -NR
3. press descending order cpu utilization
PS -e -o"% C:% P:% Z:% a "| Sort -NR
4. Print said cache instead of the URL
grep -a JPG -R & lt / Data / Cache / * | strings | grep "http:" | awk -F'http: '' {Print "http:" $ 2;} '
5. the view and the number of concurrent TCP connection request to the http status:
the netstat -n | awk '/ ^ TCP / ++ {S [$ of NF]} for the END {(S in A) Print A, S [A]}'
6. The Sed -i '/ Root / S / NO / yes / '/ etc / ssh / sshd_config sed in this paper in a row Root, Root match line, will no replace yes.
7.1 mysql how to kill process:.
PS the AUX | grep mysql | grep -v grep | awk' {print $ 2} ' | xargs kill -9 (learned from the use of awk)
killall mysqld -TERM
kill -9 `cat / usr / local / apache2 / logs / httpd.pid` try killing the process PID
8. Display run level 3 open service:
LS /etc/rc3.d/S* | cut -c 15- (learned from the use of cut, and the interception of data)
The number of CPU (multi-accounting plurality of CPU, cat / proc / cpuinfo | grep -c processor) more, the system load is low, the number of requests per second also able to handle more.
CPU 16 loads # cat / proc / loadavg
before checking whether the output value exceeds three times the system logic of the CPU 4.
15. the statistics about the size because a colleague to all of the following jpg file servers, wrote a shell to him to count turned out to achieve with xargs, but he was part of a deal, out of more than the sum of ...., the following command will be able to solve it. find / -name *. jpg -exec wc -c {} \;|awk '{print $1}'|awk '{a+=$1}END{print a}'
18 CPU load #mpstat 1 1% idle check is too low (such as less than 5%)
19 # free memory
to check whether the value is too low may be free with CAT # / proc / meminfo
20 is the swap space # free
check value too swap used If the swap used high value is too high, further action is frequently checked swap: # vmstat 1 5
observation si and so value is larger
21 disk space # df -h
to check for partition usage (Use%) is too high (for example, more than 90 %) found a nearly empty space partition, enter the partition's mount point, to find out the most space a file or directory with the following command: # du -cks * | the Sort -rn | head -n 10
22 disk I / O load check # iostat -x 1 2 I / O usage rate (% util) exceeds 100%
23 # sar -n DEV network load check network traffic (rxbyt / s, txbyt / s ) is too high
24 network error # netstat -i
to check for network errors (drop fifo colls carrier) can also use the command: # cat / proc / net / dev
number 25 network connections netstat -an # | grep -E "^ (tcp)" | Cut -c 68- | the Sort | uniq -c | the Sort -n
26 the total number of processes # ps aux | wc -l inspection process The number is normal (for example more than 250)
27 can run a process number # vmwtat 1 5
column gives the number of processes can be run, the system checks whether it exceeds 4 times the logical CPU
whether the process 28 # top -id 1 was observed abnormalities appear process
29 network whether the status check DNS, gateway can communicate normally
30 users # who | wc -l
to check whether the user login too many (such as more than 50) can also use the command: # uptime