What are the unknown but useful commands in shell
This article mainly introduces the unknown but very useful commands in shell. It is very detailed and has a certain reference value. Friends who are interested must finish reading it!
I've been using the Linux operating system recently, and I'm familiar with some simple commands, so here are a few little-known but useful commands:
1.mtr command to view the direct network connection between the host running mtr and a website, as follows
Mtr google.com
Show the content.
My traceroute [v0.75]
Localhost.localdomain (0.0.0.0) Sun May 18 19:32:36 2014
Keys: Help Display mode Restart statistics Order of fields quit
Packets Pings
Host Loss% Snt Last Avg Best Wrst StDev
1. 103.31.240.129 0.0% 42 0.5 0.5 0.6 0.0
2. 118.126.0.9 0.0% 42 0.3 0.3 0.2 0.4 0.0
3. 210.245.144.37 0.0% 42 2.9 3.6 2.9 22.1 3.0
4. 113.10.231.125 0.0% 42 3.1 3.8 2.7 40.2 5.8
5. Irb9.10g-tc2.wpc.nwtgigalink.com 0.0% 42 2.9 3.1 2.9 5.1 0.4
6. Ae2.10g-pp2.wpc.nwtgigalink.com 0.0% 42 3.2 3.0 2.9 3.2 0.1
7. Google3-10G.hkix.net 0.0% 42 4.6 4.5 4.3 4.6 0.1
8. 209.85.248.62 0.0% 42 5.0 5.3 4.8 13.7 1.6
9. 209.85.241.171 0.0% 42 5.3 5.2 5.1 5.7 0.1
10. Hkg03s16-in-f8.1e100.net 0.0% 41 4.8 4.9 4.7 5.0 0.1
2.nl command to add a line number to the viewed text, as follows
Cat a.log
Aa
Nl a.log
1 aa
3.shuf command to randomly select a line or file from a file or a folder
[root@localhost mwq] # ls | shuf-N1
A.log
[root@localhost mwq] # ls | shuf-N1
A.log
[root@localhost mwq] # ls | shuf-N1
A.log
[root@localhost mwq] # ls | shuf-N1
20140512.sql
[root@localhost mwq] # ls | shuf-N1
20140512.sql
[root@localhost mwq] # ls | shuf-N1
A.log
[root@localhost mwq] # vim a.log
[root@localhost mwq] # cat a.log | shuf-N1
Aa
[root@localhost mwq] # cat a.log | shuf-N1
Dd
[root@localhost mwq] # cat a.log | shuf-N1
Aa
[root@localhost mwq] # cat a.log | shuf-N1
Ff
Of course, you can also change the parameters such as cat a.log | shuf-N2 to get two lines.
4.last command to view the last logged-in or logged-out user
Root pts/4 xxxxxxxxxxx Sun May 18 19:12 still logged in
Root pts/4 xxxxxxxxxxx Fri May 16 09:39-15:17 (05:38)
Root pts/4 xxxxxxxxxxx Wed May 14 17:13-18:01 (00:48)
Root pts/4 xxxxxxxxxxx Mon May 12 10:50-13:38 (02:47)
Root pts/4 xxxxxxxxxxx Mon May 12 10:48-10:50 (00:02)
Root pts/1 xxxxxxxxxxx Fri May 9 11:58 still logged in
5.pstree displays the current process node in a tree structure
Init ─┬─ abrt-dump-oops
├─ abrtd
├─ acpid
├─ atd
├─ auditd ─── {auditd}
├─ avahi-daemon ─── avahi-daemon
├─ console-kit-dae ─── 63 * [{console-kit-da}]
├─ crond
├─ dbus-daemon ─── {dbus-daemon}
├─ hald ─── hald-runner ─┬─ hald-addon-acpi
│ └─ hald-addon-inpu
├─ irqbalance
├─ java ─── 330 * [{java}]
├─ master ─── qmgr
├─ 6 * [mingetty]
├─ mysqld_safe ─── mysqld ─── 11* [{mysqld}]
├─ rhsmcertd ─── rhsmcertd
├─ rsyslogd ─── 3 * [{rsyslogd}]
├─ sshd ─┬─ 4 * [sshd ─── bash]
│ └─ sshd ─── bash ─── pstree
├─ stap-serverd
├─ udevd ─── 2 * [udevd]
└─ vsftpd
The above is all the contents of the article "what are the unknown but useful commands in shell". Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!
