linux/unix utilities

1. How to kill a known process

Step #1: First, you need to find out process PID (process id)

Use ps command or pidof command to find out process ID (PID). Syntax:
# ps aux | grep processname
pidof processname

For example if process name is lighttpd, you can use any one of the following command to obtain process ID:
# ps aux | grep lighttpd

OR use pidof command which is use to find the process ID of a running program:
# pidof lighttpd

Step #2: kill process using PID (process id)

Above command tell you PID of lighttpd process. Now kill process using this PID:
# kill PID
# kill -9 PID
Where, -9 is special Kill signal, which will kill the process.

2. How to kill the process running on specific port in linux

Step #1: Find Out Which Process Is Listening Upon a Port

Type the following command:
# netstat -tulpn | grep :PID
# fuser PID
lsof -i :PID

Step #2: kill process using PID (process id)

same as previous Step #2.

3. Find out process name associated with PID and current working directory of a process

To find out process name associated with PID, type the following command:
# ls -l /proc/PID/exe

To find out current working directory of a process, type the following command:
# ls -l /proc/PID/cwd
# pwdx PID


How to free a port on windows

You can use the “netstat” command from command prompt to determine which program is using any port.

Follow these steps:

1. Click Start, type cmd in the Start Search box, and then press ENTER.
If you are prompted for an administrator password or for a confirmation, type the password, or click Continue.
2. Type netstat –ano and hit enter.
This will provide a list of ports, along with the PID (process ID) that has those ports open.
(Shortcut: netstat -ano | findstr portNumber)

Command prompt:
taskkill /PID XXX (force kill: taskkill /F /PID XXX)

1. To determine what executable is running as a process ID, open Windows Task Manager and switch to the Processes tab.
2. Now click on View->Select Columns.
3. On the screen that opens, make sure “PID (Process Identifier)” is checked and then click OK.
4. Now click on the PID heading to sort the entries by PID.