Page 42 - Raspberry Pi as a Foundation for Boosting Computer and Technology Literacy

3 Fundamentals of the Linux system and terminal usage

Table 3.3 Frequently used commands for system monitoring
Command Description
ps List all running processes
killall Kill process by name
df Get info on mounted file systems
free Get info on free and used memory
top Display Linux processes
htop Enhanced version of top

Killing a process without running a CLI program can also be very
useful, particularly if it is part of a chain of other commands or within
a shell script.
ps -u -x
killall lxterminal
This can be accomplished by first running a ps command with the
-u and -x flags to display all processes belonging to the current user.
Then, find the name of the process inside the output (e.g. “lxterminal”)
and pass it as an argument to the killall command to terminate it.
Above are some of the frequently used commands for managing
processes, monitoring CPU and RAM usage, and checking mounted
storage (Table 3.3).

Network commands
A very popular way to check if a device is connected to the Internet or
if a specific website is currently available is to use the ping command.
For instance, one could try to ‘ping’ a Google server:

ping google.com
Thus, if the command returns successful ‘pings’, which are small in-
dividual packets of data, then the website is available, and the device
has access to the Internet (Figure 3.16).
In table 3.4 are some of the frequently used commands related to
connectivity and networks.

Figure 3.16 Example of the ping command

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