6.1. The /etc/passwd file

The /etc/passwd file is a list of users recognized by the system. The system consults the file at login time to determine a user’s UID and home directory, among other things. Each line in the file represents one user and contains seven fields separated by colons:

  • Login name

  • Encrypted password or password placeholder (see page 96)

  • UID (user ID) number

  • Default GID (group ID) number

  • “GECOS” information: full name, office, extension, home phone

  • Home directory

  • Login shell

For example, the following lines are all syntactically valid /etc/passwd entries:

root:lga5FjuGpZ2so:0:0:The System,,x6096,:/:/bin/shjl:x:100:0:Jim Lane,ECT8-3,,:/staff/jl:/bin/shdotty:$1$Ce8QpAQI$L.DvJEWiHlWetKTMLXFZO/:101:20::/home/dotty:/bin/tcsh ...

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