How to: Find Out Whether a UNIX / Linux Process Is Running or Not

Q. I’d like to find out if httpd / mysqld or sshd process is running or not under CentOS Linux server. How do I determine whether a process is running or not?

A. You need to use following commands:

[a] ps – It report a snapshot of the current processes [b] grep – Filter out process names

Find out if sshd is Process is Running or Not

Type the following command at shell prompt:
$ ps -ewwo pid,args | grep [s]sh
Output:

5341 /usr/sbin/sshd
 5864 /usr/bin/ssh-agent x-session-manager
 6289 ssh oldbox
 7126 ssh admin@core.r1.vsnl.router 

Where,

• ps : Command name
• -ewwo pid,args : -e option force to select all running processes. -o option is used to specify user-defined format. In our case we are forcing to display only program pid and its arguments. Finally -w option specifies wide output. Use this option twice for unlimited width.
• grep [s]sh : We are just filtering out sshd string

Category	List of Unix and Linux commands
File Management	cat
Firewall	Alpine Awall • CentOS 8 • OpenSUSE • RHEL 8 • Ubuntu 16.04 • Ubuntu 18.04 • Ubuntu 20.04
Network Utilities	dig • host • ip • nmap
OpenVPN	CentOS 7 • CentOS 8 • Debian 10 • Debian 8/9 • Ubuntu 18.04 • Ubuntu 20.04
Package Manager	apk • apt
Processes Management	bg • chroot • cron • disown • fg • jobs • killall • kill • pidof • pstree • pwdx • time
Searching	grep • whereis • which
User Information	groups • id • lastcomm • last • lid/libuser-lid • logname • members • users • whoami • who • w
WireGuard VPN	Alpine • CentOS 8 • Debian 10 • Firewall • Ubuntu 20.04