Frequently used shell commands (updated in succession)

It's just my personal use, not all of it.

1. Get the return value in front of the pipeline

Echo ${pipestatus[0]}

e.g.

[Email protected]:~# date1 | echo 22No command ' date1 ' found, did your Mean:command ' date ' from the package ' coreutils ' (main) Date1:command not Found[emai L protected]:~# Echo ${pipestatus[0]}127

2. Review the Process

Ps-ef | grep Pidname | Grep-v grep

Note:-V is excluded,-EF is the parameter of PS

e.g.

[Email protected]:~# 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< C9/>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 off

echo B >/proc/sysrq-trigger

4. View the script after he runs, and go to the foreground to run

jobs: See all scripts running in the background
FG. : Run in front

Add a & behind the script, you can run in the background, even if Xshell accidentally shut down can continue to run, if you want to see in the background to run those, or turn off these processes, use the above two commands to the foreground

5. View memory usage and clean up memory

View memory usage free-m

Clear Memory
echo 3 >/proc/sys/vm/drop_caches release all memory that can be freed
0– not release
-Free Page Cache
Release Dentries and Inodes
3– Release All Caches

Simply put, clear the system to the memory cache, using root to do 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 results to a file

Sh-x/script_path > File 2>&1

7. Find out if all files in the directory contain a string

Find if all files in the directory contain a string
Find. | Xargs Grep-ri "string"
Finds all files in the directory that contain a string, and prints only the file name
Find. | Xargs Grep-ri "string"-l

Frequently used shell commands (updated in succession)