1. Find Status of last run command in shellFor ksh bash $?

$# -> 2 no of Argument $* -> foo bar array of argument $0 -> myapp application name $1 -> foo first argument $2 -> bar

2. How many user we have

awk -F":" '{print $1,$4}' /etc/passwd

WHO commandNAME

who - show who is logged on

SYNOPSIS

who [OPTION]... [ FILE | ARG1 ARG2 ]

DESCRIPTION

Print information about users who are currently logged in.

-a, --all

same as -b -d --login -p -r -t -T -u

-b, --boot

time of last system boot

-d, --dead

print dead processes

-H, --heading

print line of column headings

--ips print ips instead of hostnames. with --lookup, canonicalizes based on stored IP, if available,

rather than stored hostname

-l, --login

print system login processes --lookup

attempt to canonicalize hostnames via DNS

-m only hostname and user associated with stdin

-p, --process

print active processes spawned by init

-q, --count

all login names and number of users logged on

-r, --runlevel

print current runlevel

-s, --short

print only name, line, and time (default)

-t, --time

print last system clock change

-T, -w, --mesg

add user's message status as +, - or ?

-u, --users

list users logged inTo Get Uid (User id) of current userId

Eg:-

oracle@ubuntu:/etc$ id

uid=1001(oracle) gid=1001(oinstall) groups=1001(oinstall),1002(dba)To find a user's UID or GID in Unix, use the id command. To find a specific user's UID, at the Unix prompt, enter:

id -u username

oracle@ubuntu:/etc$ id -u oracle

1001Replace username with the appropriate user's username. To find a user's GID, at the Unix prompt, enter:

id -g username

eg:-

oracle@ubuntu:/etc$ id -g `whoami`

1001If you wish to find out all the groups a user belongs to, instead enter:

id -G username eg:-

oracle@ubuntu:/etc$ id -G `whoami`

1001 1002If you wish to see the UID and all groups associated with a user, enter id without any options, as follows:

id usernameFinger -s Finger displays the user's login name, real name, terminal name and write status (as a ``*''

after the terminal name if write permission is denied), idle time, login time, office location

and office phone number.

Login time is displayed as month, day, hours and minutes, unless more than six months ago, in

which case the year is displayed rather than the hours and minutes.

Unknown devices as well as nonexistent idle and login times are displayed as single asterisks.

-l Produces a multi-line format displaying all of the information described for the -s option as

well as the user's home directory, home phone number, login shell, mail status, and the contents

of the files .plan.project.pgpkey.forward

Phone numbers specified as eleven digits are printed as ``+N-NNN-NNN-NNNN''. Numbers specified

as ten or seven digits are printed as the appropriate subset of that string. Numbers specified

as five digits are printed as ``xN-NNNN''. Numbers specified as four digits are printed as

``xNNNN''.

If write permission is denied to the device, the phrase ``(messages off)'' is appended to the

line containing the device name. One entry per user is displayed with the -l option; if a user

is logged on multiple times, terminal information is repeated once per login.

Mail status is shown as ``No Mail.'' if there is no mail at all, ``Mail last read DDD MMM ##

HH:MM YYYY (TZ)'' if the person has looked at their mailbox since new mail arriving, or ``New

mail received ...'', `` Unread since ...'' if they have new mail.

root@ubuntu:/home/tomhawk12/Scripts# finger -s

Login Name Tty Idle Login Time Office Office Phone

oracle pts/0 Nov 26 04:29 (192.168.32.1)

oracle pts/3 11 Nov 26 06:00 (192.168.32.1)

tomhawk12 KUMAR tty7 3:12 Nov 26 04:58 (:0)

tomhawk12 KUMAR pts/1 1:31 Nov 26 05:54 (:0.0)

tomhawk12 KUMAR pts/2 1:28 Nov 26 05:54 (:0.0)

root@ubuntu:/home/tomhawk12/Scripts# finger -l

Login: oracle Name:

Directory: /home/oracle Shell: /bin/bash

On since Mon Nov 26 04:29 (PST) on pts/0 from 192.168.32.1

On since Mon Nov 26 06:00 (PST) on pts/3 from 192.168.32.1

11 minutes 19 seconds idle

No mail.

No Plan.

Login: tomhawk12 Name: KUMAR

Directory: /home/tomhawk12 Shell: /bin/bash

On since Mon Nov 26 04:58 (PST) on tty7 from :0

3 hours 12 minutes idle

On since Mon Nov 26 05:54 (PST) on pts/1 from :0.0

1 hour 31 minutes idle

On since Mon Nov 26 05:54 (PST) on pts/2 from :0.0

1 hour 28 minutes idle

No mail.

No Plan.