Shell Scripting Tutorial-46: 'passwd' File Revisited Video Lecture | Shell Scripting: Discovering to Automate Command-Line Tasks - Back-End Programming

hello guys my name is mother and welcome
to my channel this is the 46 tutorial in
the series of tutorials on UNIX shell
scripting in this tutorial we're going
to build a shell script that extracts
information from the password file in
the EDC folder in the file system and
displays aid on-screen in such a way
that the user can understand and I have
my text editor here and I've saved this
file in the home folder
it's called P info and has the extension
SH now one noticeable thing about the
password file is that the delimiter
between the fields or the separator is
not the space character or the dark
actor but is the colon character so
somewhere in the script we will have to
change the value of ifs but before we do
that what I'm going to do is I'm going
to use echo to display a message on
screen to the user and it's going to be
to ask for a username and this username
has to be the username for which
information is sought right so I'll just
type in enter username and I put olam
there and be /c sequence on the next
line and use Reed to store the input in
a variable called log name now what I'm
going to do is I'm going to use grep to
extract that line of information from
the password file which consists of the
username that has been just provided to
us and the way to do that would be grep
space dollar logname and dollar logname
here consists of the input that has been
provided and then I'll have to type in
the path of the file in which I want
this pattern to be searched and that's
going to be slash EPC slash PA SS WB and
what I'll do is I'll assign this line of
information to a variable called line
and since I'm concerned with the output
of this command I'll have to put the
entire expression within reverse codes
right and on the next line I'll change
the value of ifs and I'll give it the
value : because that's what the field
separator is between the fields in each
row in the password file and now we can
set our positional parameters with the
value that's stored in the variable line
member line here contains information
about the user whose
user name has been provided as input in
the square so set space dollar line will
do the job for us and now since our
positional parameters are set we can
echo them out one by one on screen and
since the username field is the first
field its value must have been stored in
the positional parameter dollar one and
that's why I've used my echo statement
on line six to first display a word
username and then the value that's
stored in positional parameter dollar
one and on on line six I have one echo
statement on line seven I'll display the
user ID and I have skipped the password
field because if you guys remember the
password is always encrypted and it is
denoted by the character X in the
password file and that's true for not
just the user accounts but also for
system accounts so root will also have
an encrypted password and all the other
system accounts will have encrypted
passwords and you will have an encrypted
password as well so there's no point
just showing the symbol X on screen for
the password right if you guys want then
you can show a message like the password
is encrypted but I don't think that's
required so we're skipping the password
theme which was the second one now you
have to display the third field which is
a user ID field and its value must have
been stored in the positional parameter
door at 3:00 so that's what we're gonna
echo out on the next line I'm gonna
display the group ID field and since
that's the fourth feed I'll type in
dollar four here and the next field is
the comment field and that's the fifth
field so I like out dollar five and the
next field is the field for the home
folder right and since it's a sixth
field its value must have been stored in
the sixth positional parameter so taller
six and the last field is the field for
the default shell and it's the seventh
field and its value must be in dollar
seven so there you go I've saved the
script
I'll bring up my terminal here and I'll
execute it by typing in SN space P info
thought SH and when I press the Enter
key the script asks me or a username and
since I'm the only user on this system
and I haven't created any other user
account I'll just type in my own name
you see details about myself and when I
press the Enter key you see that I get
all this information the user name is
mother the user ID is one triple zero
the group ID is one triple 0 the common
field is the destruction and the home
folder is slash home slash mother and
the default shell is as you can see it's
bash and its entire path is being
displayed so the reason why I created
this script is because when you look at
the contents of the password file you
cannot make much sense are afraid unless
you know the meaning or the significance
of each of the seven fields in each row
right so in case you forget you can
always you know keep this script file in
your home folder or somewhere in your
file system and you can execute it and
have an idea about you know what the
meaning of each field is I hope this
tutorial was entertaining for you I see
you guys in the next one where we will
discuss something important again thank
you so much for watching this one and
I'll see you in the next one please
subscribe to my channel