Linux Command Line Tutorial For Beginners 28 - Head and Tail Commands Video Lecture | Complete Linux Course: Become a Linux Professional - Software Development

hey guys welcome to the next video on
Linux command line tutorial for
beginners and in this video I am going
to show you how we can use head and tail
commands in Linux so head and tail
commands generally we can use with files
and the head and tail are actually doing
the opposite of each other so the head
command can be used to output the first
part of the file and the tail command
can be used to output or print the tail
part or last part of the file now
generally by default whenever you use a
head or tail command they will print
first ten lines using head command or
last ten line using tail commands okay
so let's see how we can use a head and
tail command so what I am going to use
do is I am going to go to the bar slash
log directory of my system where lots
and lots of log files are there okay so
I am going to do LS and I can see so
many log files are there right and I
want to use the head and tail command to
see the content of these files right so
for example I will use head command and
then for example let's see which file we
want to see so there will be a file
called D message file D mesg and just
use head with this file so this is a
file and you can use any other log file
and this head file can be used in many
ways but generally it's used with log
files and other kind of files right so
just write hat and the name of the log
file you want to see and then press
ENTER and it's going to show you the
first 10 lines of this text file ok and
the tail command can be used to show the
last 10 lines so when I use instead of
head
I use tail the message and then it's
going to show the last 10 lines of this
D message file okay so let me clear the
terminal once again now for example I
want to change the number of lines I
want to see okay so this is also
possible for example I want to see just
three lines are using head command so I
can use head and then minus N and the
number of line for example 3 I want to
see first 3 lines and the name of your
file so just write D message and press
ENTER and it's going to show the first 3
lines and same you can do with the tail
command so you can just write tail and
then minus and 3 and the name of the
file is going to show you the last three
lines of the file ok basically you can
also use the stale or head command like
this so just write tail and then minus
the number of line you want to show you
don't even need to use the N flag with
it so the same output will be there ok
so this can be used in this way also
now the other use of this head and tail
command is using the flag F so I'm going
to once again clear the terminal and
what I'm going to do is I'm going to
just use the tail command for example
and then with minus F flag and then the
name of the file for example so I'm
going to just use this file once again
and press ENTER and what it's doing is
it's printing the last 10 line but it's
not you know going out of the terminal
output right so it's hanging around and
it's going to watch for this file and
whenever this file changes then this
output will also change so it's going to
append the last line for example is
going to show you the
last ten lines again okay so this F flag
is for follow and it's going to show you
the last ten line and this kind of you
know tail with F can be used whenever
you are doing input and output thing
using some you know input source or
output source using serial or you know
any other you know communication you are
doing with your Linux operating system
so whenever you want to see the output
what's the output is on the tail of your
file then you can use the app flag so
it's going to show you appended lines of
code here also okay now one more thing
you can do with the head and tail
commands is you can use multiple files
with healthy until command so for
example I use head and then the name of
the file first file I want to use is
once again this file and the next file I
want to use for example I can search for
this file let's say you want to use this
turn log file okay so the first file
second file and you can use multiple
files to see the first 10 lines of these
files so I am going to just press ENTER
and you can see first
it has printed the first 10 line of the
message file and then it has printed the
10 lines of this kernel log file ok so
this is how also you can use this
command once again I'm going to clear
the clear the terminal and once again I
can use this command but with this flag
which shows the number of lines and just
press Enter is going to show you the
first 3 line from the D message command
and first 3 line from the kernel log
file
okay so this is how you can use
generally the head and tail commands in
your Linux operating system I hope
you've enjoyed this video please
recommend subscribe and bye for now
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