Uptime. this is a useful command for finding out how long a Linux system has been running for. it also displays the load average over 1.5 and 15 minute intervals.
deep-thought ~ # uptime 21:45:32 up 32 min, 3 users, load average: 1.88, 1.45, 1.08 |
The w command will show the users that are logged into your Linux system and where they are logged in.
deep-thought ~ # w 22:04:39 up 51 min, 2 users, load average: 0.82, 0.76, 0.88 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT homer tty7 :0 21:14 51:08 22:12 0.07s gdm-session-worker [pam/gdm-password] homer pts/0 :0.0 22:03 7.00s 0.28s 0.34s mate-terminal |
To stop a service on a Linux system use the service command. This is used to stop and start services easily.
deep-thought ~ # service apache2 stop * Stopping web server apache2 apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1 for ServerName ... waiting |
And this is how to start the service on Linux.
deep-thought ~ # service apache2 start * Starting web server apache2 apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1 for ServerName |
The free command is used to show how much free memory there is on your system. A very useful command indeed.
deep-thought ~ # free total used free shared buffers cached Mem: 6043416 4419804 1623612 0 862984 2024672 -/+ buffers/cache: 1532148 4511268 Swap: 15885300 0 15885300 |
This is the command the systems administrator used in the movie TRON Legacy. Here I am looking for a certain process ID. This also shows the processes running under the mate-terminal process.
deep-thought ~ # ps -ef | grep 7378 homer 7378 3406 0 22:03 ? 00:00:01 mate-terminal homer 7384 7378 0 22:03 ? 00:00:00 gnome-pty-helper homer 7385 7378 0 22:03 pts/0 00:00:00 zsh root 7742 7505 0 22:29 pts/0 00:00:00 grep --colour=auto 7378 |
The who am i command displays the name of your user and what tty you are logged in on.
deep-thought ~ # who am i homer pts/0 2013-07-18 22:03 (:0.0) |
Using the find command to seek out a specific file in a folder.
deep-thought Desktop # find /home/homer/Desktop -name "snow*" /home/homer/Desktop/snowden.jpg /home/homer/Desktop/snowden.png |
The lsof command lists all open files. Here I am listing all files that are opened by the mate-terminal process.
bash 10:40:38 Thu Jul 18 [homer@deep-thought $ lsof | grep mate-terminal mate-term 7378 homer txt REG 8,97 313824 6030129 /usr/bin/mate-terminal mate-term 7378 homer mem REG 8,97 61757 267120 /usr/share/locale/en_AU/LC_MESSAGES/mate-terminal.mo gdbus 7378 7382 homer txt REG 8,97 313824 6030129 /usr/bin/mate-terminal gdbus 7378 7382 homer mem REG 8,97 61757 267120 /usr/share/locale/en_AU/LC_MESSAGES/mate-terminal.mo dconf 7378 7383 homer txt REG 8,97 313824 6030129 /usr/bin/mate-terminal dconf 7378 7383 homer mem REG 8,97 61757 267120 /usr/share/locale/en_AU/LC_MESSAGES/mate-terminal.mo gmain 7378 7386 homer txt REG 8,97 313824 6030129 /usr/bin/mate-terminal gmain 7378 7386 homer mem REG 8,97 61757 267120 /usr/share/locale/en_AU/LC_MESSAGES/mate-terminal.mo |
This is how to show the last reboot time on your Linux desktop or server machine.
bash 10:45:18 Thu Jul 18 [homer@deep-thought $ last reboot | head -n 1 reboot system boot 3.8.0-25-generic Thu Jul 18 21:13 - 22:45 (01:31) |
if you want to create many folders at once with the bash shell, then use this command.
bash 10:49:37 Thu Jul 18 [homer@deep-thought $ mkdir a b c d e f g |
This is a very useful tip, how to only list directories with the ls command using the Linux command prompt. A very useful tip indeed.
bash 10:49:37 Thu Jul 18 [homer@deep-thought $ ls -ld */ drwxrwxr-x 2 homer homer 4.0K 18-07-13 10:49 pm a/ drwxrwxr-x 2 homer homer 4.0K 18-07-13 10:49 pm b/ drwxrwxr-x 2 homer homer 4.0K 18-07-13 10:49 pm c/ drwxrwxr-x 2 homer homer 4.0K 18-07-13 10:49 pm d/ drwxrwxr-x 2 homer homer 4.0K 18-07-13 10:49 pm e/ drwxrwxr-x 2 homer homer 4.0K 18-07-13 10:49 pm f/ drwxrwxr-x 2 homer homer 4.0K 18-07-13 10:49 pm g/ drwxrwxr-x 2 homer homer 4.0K 18-07-13 09:15 pm networking/ drwxr-xr-x 4 homer homer 4.0K 18-07-13 09:15 pm Site/ |