- #RASPBERRY PI SYSTEM MONITOR COMMAND LINE HOW TO#
- #RASPBERRY PI SYSTEM MONITOR COMMAND LINE INSTALL#
- #RASPBERRY PI SYSTEM MONITOR COMMAND LINE FULL#
Placing an ampersand after a command in the shell places the program in the background – try with: man top & and you’ll get an output like 12768. htop also shows load over the separate cores of the processor if you have a Pi 2 or 3. When you’ve finished, exit both top and htop with q, although in htop you may care to practise by highlighting the htop process and killing it from there (see below). Htop is scrollable, both horizontally and vertically, and allows you to issue commands (such as k for kill) to highlighted processes.
#RASPBERRY PI SYSTEM MONITOR COMMAND LINE INSTALL#
For an improved top: apt-get install htop
For this, use top, which also shows total CPU and memory use in the header lines, the latter in the format that you can also find by issuing the command free. The output of ps also shows you useful information like percentage of memory and CPU time used, but it’s more useful to see these changing in real time. In the vi example above, grep found the grep process itself as well as vi (and anything with the letter sequence vi in its name). We don’t have space for an in-depth look at awk (we’re using it here to print the second field of grep’s output, the PID), but the trick at the beginning of Firefox (or whatever named process you want to kill) singles out the Firefox process. Naturally, you can pipe ps’s output to select the PID and feed directly to the kill command: kill $(ps aux | grep ‘irefox’ | awk ‘’) You can also use killall to kill by program name for example, with killall firefox. The -i (ignore case) isn’t usually necessary, but occasionally a program may break convention and contain upper-case letters in its file name. For example, locating vi processes: ps aux | grep -i vi To quickly find the process in the first place, use grep on the ps list. For example, to kill a program with a PID of 3012, simply enter kill 3012. Knowing the PID makes it easy to kill a process, if it’s the easiest way of shutting it down. This starts with 1 for init, the parent process of everything that happens in userspace after the Linux kernel starts up when you switch the Pi on. The ps aux listing has various headers, including the USER which owns the process, and the PID (process identification number). Unix’s other branch, System V, extended and changed ps with new options and new abbreviations for command switches, so for ps ax you may also see ps -e (or -ef or -ely to show in long format). Both the lack of dashes, and the letters a and x, date back to the original Unix ps of the early 1970s this was maintained through various revisions by one of Unix’s two family branches, BSD, and baked into the first GNU/Linux ps. You’ll notice that these options work without the leading dash seen for other commands. Type ps auxww to see, then try with just a or other combinations. w adds wider output, and ww will wrap over the line end to display information without truncating. On Raspbian, it’s usually called with the a and x switches which give all processes, rather than just those belonging to a user, the u switch shows processes by user, attaching it to a tty. If you like this tutorial, you can find more in our Essentials book, Conquering the Command Lineįind the many processes running on your Pi with the ps command.
#RASPBERRY PI SYSTEM MONITOR COMMAND LINE FULL#
The full article can be found in The MagPi 46 and was written by Richard smedley. We’ll show you how, and look at what else can be done with knowledge of processes. There’s no need to panic, and certainly no need to reboot: just identify the process and quietly kill it.
#RASPBERRY PI SYSTEM MONITOR COMMAND LINE HOW TO#
Ever lost the ‘off switch’ for a program? Sometimes software you’re running seems to have no inclination to stop: either you can’t find out how to quit, or the app has a problem and won’t respond to your q, CTRL+C, or whatever command should close it down.
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