Answer:
cat /etc/passwd | grep <username>
If the user is not there the above command will not return
any value else will return the attributes of the user.
Q2: How to find if the customer want which date the user is created e.g. the exact date & time?
Answer:
There is no default or standard way for determining the user creation date in Linux. The best practice is to include the -c or comment option when creating a user. You can put the creation date in the comment.
There are some things you can do to get the creation date but all of them depend on a specific set of circumstances and/or software to determine that date and time.
For example, if created and not touched since the user creation you can use the .bash_logout file to determine the date.
As root run
ls -l /home/<username>/.bash_logoutls -l /home/<username>/.bash_logout
If the user was created recently and your log files have not been rotated out (usually about 4 weeks) you can check /var/log/messages for 'useradd'. The useradd line will include the date and time.
If you have tripwire installed and running AND it is setup to watch /etc/passwd then there will be an entry for each time a password is created or changed and by whom.
If the user has a home directory, you can check that directories creation date
ls -ld /home/username/ls -ld /home/username/
If using auditd you can search for the user creation
aureport –auth | grep melbinaureport –auth | grep melbin
There are other methods but again, it all depends on your setup.
