Depending on the Linux distribution you use, its version, installed programs, computer resources among other agents, many things can go wrong that cause the computer to "hang" or at least some program in question (it happens quite often with programs resource-intensive ones like Eclipse, Android Studio, emulators, etc.).
In these cases the right thing to do is simply "kill" or destroy the process(es) associated with the program in order to free up resources and possibly start the program again.
The Kill and Killall commands to "kill" processes
There are a couple of commands that allow you to perform this task in a simple way; they are Kill and Killall.
The kill command
To use the Kill command it is necessary to know the identifier of the process that we want to kill or destroy; for this we use the ps aux command:
...
3036 ? S 0:00 /opt/google/chrome/chrome --type=zygote --enable-crash-reporter=DFD73122-B4B8-416D-A254-9ABF21A8B36E
3056 ? Sl 4:35 /proc/self/exe --type=gpu-process --channel=3019.0.65190361 --enable-crash-reporter=DFD73122-B4B8-416D-A254-9ABF2
3062 ? S 0:00 /proc/self/exe --type=gpu-process --channel=3019.0.65190361 --enable-crash-reporter=DFD73122-B4B8-416D-A254-9ABF2
3145 ? Sl 0:08 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=AffiliationBasedMatching/Enabled/Audi
3149 ? Sl 0:00 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=AffiliationBasedMatching/Enabled/Audi
3152 ? Sl 0:00 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=AffiliationBasedMatching/Enabled/Audi
3225 ? Sl 0:00 /usr/libexec/gvfsd-trash --spawner :1.5 /org/gtk/gvfs/exec_spaw/0
3268 ? Sl 1:01 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=AffiliationBasedMatching/Enabled/Audi
3525 ? S 0:00 /home/andres/sts-bundle/sts-3.6.4.RELEASE/STS
3527 ? Sl 5:07 /usr/bin/java -Dosgi.requiredJavaVersion=1.6 -Xms40m -Xmx768m -XX:MaxPermSize=256m -jar /home/andres/sts-bundle/s
4306 ? Sl 6:14 /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.60-14.b27.fc21.x86_64/bin/java -Dcatalina.base=/home/andres/sts-bundle/pivo
4349 ? Ss 0:02 postgres: postgres oo 127.0.0.1(50352) idle
4468 ? Sl 0:17 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=*AffiliationBasedMatching/Enabled/Aud
4510 ? Sl 0:28 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=*AffiliationBasedMatching/Enabled/Aud
5568 ? Sl 0:16 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=*AffiliationBasedMatching/Enabled/Aud
5624 ? Ss 0:04 postgres: postgres oo 127.0.0.1(51676) idle
6278 ? Sl 0:02 /usr/bin/nautilus --gapplication-service
7712 ? Sl 0:03 /usr/bin/pgadmin3
8133 ? Sl 0:49 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=*AffiliationBasedMatching/Enabled/Aud
8207 ? Sl 0:40 /opt/google/chrome/chrome --type=ppapi --channel=3019.108.1263279707 --ppapi-flash-args --lang=es-419 --enable-cr
8381 ? S 0:00 [kworker/u4:2]
8600 ? S 0:01 [kworker/1:0]
9268 ? S 0:00 [kworker/0:3]
9545 ? Sl 0:00 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=*AffiliationBasedMatching/Enabled/Aud
9582 ? S 0:00 [kworker/1:2]
9622 ? Sl 0:00 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=*AffiliationBasedMatching/Enabled/Aud
9629 ? Sl 0:02 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=*AffiliationBasedMatching/Enabled/Aud
9642 ? Sl 0:00 /opt/google/chrome/chrome --type=ppapi --channel=3019.137.1613879471 --ppapi-flash-args --lang=es-419 --enable-cr
9650 ? Sl 1:12 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=*AffiliationBasedMatching/Enabled/Aud
9873 ? S 0:00 [kworker/0:0]
9876 ? S 0:00 [kworker/u4:0]
9967 ? Rl 0:00 /usr/libexec/gnome-terminal-server
9970 ? S 0:00 gnome-pty-helper
9971 pts/0 Ss 0:00 bash
10051 ? Sl 0:01 /opt/google/chrome/chrome --type=renderer --lang=es-419 --force-fieldtrials=*AffiliationBasedMatching/Enabled/Aud
10078 ? S 0:00 [kworker/0:1]
10081 ? Sl 0:00 /usr/bin/gedit --gapplication-service
10088 ? S 0:00 [kworker/u4:1]
...Filtering processes with the ps and grep command
Although to our surprise, there are too many processes managed by the system that were not necessarily started by us and are part of the system; to filter them we can use the ps command in conjunction with the grep command as follows:
ps aux | grep geditThis gives us a much smaller list:
andres 10081 0.3 0.7 666388 35004 ? Sl 11:21 0:00 /usr/bin/gedit --gapplication-service andres 10231 0.0 0.0 113020 2248 pts/0 S+ 11:24 0:00 grep --color=auto geditNow we can kill the Gedit program associated with process ID 10081 (PDI) (as we can see in the output returned above) by simply running the following command:
kill 10081If the process does not exist, we will see an output similar to the following:
kill 41076
bash: kill: (41076) - No existe el procesoThe command syntax:
kill PDIThe Killall Command
With the Killall command it is easier, just knowing the name of the process that we want to kill is enough; for example, to kill him; to kill the process named "firefox":
killall firefoxTo kill the process "gedit":
killall geditTo kill the process "pgadmin3":
killall pgadmin3To kill the process "google-chrome":
killall google-chromeTo kill the process "nautilus":
killall nautilusTo kill the process ("pgadmin3" in this example) does not exist, we will see output similar to the following:
killall pgadmin3
pgadmin3: no process foundHow can you tell, it is necessary to know the name of the process you want to kill from the system to use the commando Killall.
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