/etc/courier/userdb can also be a subdirectory, instead of a file. Specify foo/bar/addr to manipulate addr in the file /etc/courier/userdb/foo/bar. You can also use the -f flag: -f /etc/courier/userdb/foo/bar is equivalent. Use whatever form makes the most sense to you.
/etc/courier/userdb must not have any group or world permissions. That's because its contents may include system passwords (depending upon the application which uses this virtual user account database).
Each line in /etc/courier/userdb takes following form:
addr specifies a unique virtual address. It is followed by a single tab character, then a list of field=value pairs, separated by vertical slash characters. See makeuserdb(8) for field definitions.
A text editor can be used to add blank lines or comments in /etc/courier/userdb. Any blank lines or comments are ignored by the userdb script.
The names of the actual fields, and their contents, are defined entirely by applications that use the /etc/courier/userdb database, the userdb command just adds or removes arbitrary fields.
userdb default/info set mail=/home/mail/info
This command accesses the address "info" in /etc/courier/userdb/default.
If the second argument to userdb is "set", the remaining arguments are taken as field=value pairs, which are added to the record for addr. If there is no record for addr, a new record will be appended to the file. If addr exists, any existing values of any specified fields are removed. If =value is missing, userdb stops and prompts for it. This is useful if you're setting a password field, where you do not want to specify the password on the command line, which can be seen by the ps(1) command. If userdb is being executed by a script, the value can be provided on standard input.
Use "unset" to delete fields from an existing record. Use "del" to delete all fields in the existing record, plus the record itself.
If the first argument to userdb is -show, userdb displays the contents of /etc/courier/userdb. If /etc/courier/userdb is a subdirectory, path must refer to a specific file in /etc/courier/userdb. The -f option can be used instead of path in order to specify an arbitrary file.
If addr is not specified, userdb produces a list, on standard output, containing all addresses found in the file, on per line. If addr is specified, userdb produces a list, on standard output, of all the fields in /etc/courier/userdb for this addr.
The actual virtual account/address database is /etc/courier/userdb.dat. This is a binary database file. /etc/courier/userdb is the plain text version. After running userdb, execute the makeuserdb(8) command to rebuild /etc/courier/userdb.dat for the changes to take effect.
addr must be unique. If /etc/courier/userdb is a subdirectory, it's possible to create the same addr in different files in the subdirectory. This is an error that is not currently detected by userdb, however the subsequent makeuserdb(8) command will fail with an error message.
/etc/courier/userdb - plain text file, or directory of plain text files
.lock.filename - lock file for filename
.tmp.filename - temporary file used to create new contents of filename