passwd contains various pieces of information for each user account. Included is
Optional encrypted password
Numerical user ID
Numerical group ID
User name or comment field
User home directory
User command interpreter
The password field may not be filled if shadow passwords have been enabled. If shadow passwords are being used, the encrypted password will be found in /etc/shadow. The encryped password consists of 13 characters from the 64 character alphabet a thru z, A thru Z, 0 thru 9, . and /. Refer to crypt(3) for details on how this string is interpreted.
The comment field is used by various system utilities, such as finger(1). Three additional values may be present in the comment field. They are
pri= - set initial value of nice
umask= - set initial value of umask
ulimit= - set initial value of ulimit
These fields are separated from each other and from any other comment field by a comma.
The home directory field provides the name of the initial working directory. Login uses this information to set the value of the HOME environmental variable.