Common shell commands (updated in succession)

Common shell commands (updated in succession)

1. Obtain the returned values before the MPs queue.

Echo $ {PIPESTATUS [0]}

E.g.

 

root@node2:~# date1 | echo 22No command 'date1' found, did you mean: Command 'date' from package 'coreutils' (main)date1: command not foundroot@node2:~# echo ${PIPESTATUS[0]}127

2. View Processes

 

Ps-ef | grep pidname | grep-v grep

Note:-v indicates exclusion, and-ef indicates ps parameter.

E.g.

 

root@node1:~# ps -ef | grep ceph | grep -v greproot     34880     1  0 11:14 pts/1    00:01:15 /usr/bin/ceph-mon -i node1 --pid-file /var/run/ceph/mon.node1.pid -c /etc/ceph/ceph.conf --cluster cephroot     37315     1  0 11:17 ?        00:00:38 /usr/bin/ceph-osd -i 0 --pid-file /var/run/ceph/osd.0.pid -c /etc/ceph/ceph.conf --cluster cephroot     37538     1  0 11:17 ?        00:00:36 /usr/bin/ceph-osd -i 1 --pid-file /var/run/ceph/osd.1.pid -c /etc/ceph/ceph.conf --cluster cephroot     46838     1  0 11:39 ?        00:00:02 /usr/bin/ceph-mds -i node1 --pid-file /var/run/ceph/mds.node1.pid -c /etc/ceph/ceph.conf --cluster ceph

3. Power Failure

Echo B>/proc/sysrq-trigger

4. Check the script that he runs and transfer it to the front-end for running.

Jobs: view all scripts running in the background
Fg 1/2...

The script can be run in the background by adding an &. Even if Xshell is accidentally shut down, it can continue to run. If you want to view the processes that are running in the background, or close these processes, run the preceding two commands to go to the front-end.

5. view memory usage and clear memory

View memory usage free-m

Clear memory
Echo 3>/proc/sys/vm/drop_caches release all available memory
0-do not release
1-release page Cache
2-release dentries and inodes
3-release all caches

Simply put, clear the system's memory cache and use root to perform the following steps:
1. sync
2. echo 3>/proc/sys/vm/drop_caches
3. sync
4. echo 0>/proc/sys/vm/drop_caches

6. Run the script in debug mode and save the result to the file.

Sh-x/script_path> file 2> & 1

7. check whether all files in the directory contain a certain string.

Check whether all files in the directory contain a certain string
Find. | xargs grep-ri "string"
Check whether all files in the directory contain a certain string and print only the file name.
Find. | xargs grep-ri "string"-l