command mode, where commands are given. You can command it to open
or replace the file. The second mode is the insert view which allows users
to type texts. Users should understand that vi does not have an appealing
GUI interface but is still efficient. It edits texts powerfully and facilitates
learning. Knowing that many people find vi editors difficult to use the first
time they encounter it; you can use a tutorial to understand how it works. It
opens v with the tutorial in it.
Another advanced Linux concept is Grep. It is a useful concept that
searches any file a user needs. It is commonly used alongside other
concepts to search for specific strings. In case a user wants to check out the
log
file on a web server, the grep does the job correctly. If you want to
determine the occurrence of “right now” in the text, all you have to do is
type grep “right now” text, and it pops up. You can proceed to check the
grep’s location by typing location grep. There are many options to choose
from. Another advanced Linux concept is PS. This is a command tool that
displays all the tasks being run on a system. It does the same work as
Windows Task Manager. There is a GUI version of ps. You can see the
process running on a system simply by logging
in as root in the Linux
system and typing ps-aux. However, users can only see processes run by
them for security purposes. In the past, it was discovered that some people
mishandled other people’s processes and security measures were
introduced.
Kill is another important concept of Linux. It is a command that
complements the ‘ps’ command and allows users to end the process that is
revealed by previous commands. You can use
syntax to kill a process in
case it is not responding. You can use kill-0 PID to eliminate the
unresponsive process. -HUP can also be used with the ‘kill’ concept. It
does not get rid of the process, but pauses and forces it to reload its
configuration. The -HUP comes in handy if you have a running service and
wants to restart owing to changes made in the configuration file. It is a great
alternative to the reload command. It is
possible to chain groups of
commands in Linux because of the great power of Linux concepts. You can
employ tools to perform tasks and pass to another one. For instance, when
you run the ps aux command, unreadable outputs may pop up on the
screens. The pipe symbol can be used to send the output to ‘grep’ to search
for it. This process is called ‘piping,’ where a pipe is used to connect two
things.
Alias is a great concept in Linux to use. It is a neat command which allows
users to make shortcut keywords for long commands. For example, if you
do not want to type ps aux/less in full, you can create an alias and name it
‘pl.’ so instead of typing it in full,
you just time pl, and it runs the ps
aux/less. It makes work seamless. Users may want to redirect outputs of
commands to text files for more processing. To do this,
open a DOS
command prompt and use the ‘>’ operator. The good thing is that these
functions are supported by Linux. Watch is an excellent command tool to
execute programs periodically and place the contents on the screen. You can
run several commands if you put the command inside quotes.
