Free Knowledge Resources


Linux Manual Pages


Free Software * Books

Source Code

Free Media

Linux

userdb(8)


NAME

   userdb - manipulate /etc/courier/userdb

SYNOPSIS

   userdb {addr} set {field=value...}

   userdb {addr} unset {field...}

   userdb {addr} del

   userdb {path/addr} [set | unset | del] ...

   userdb -f {file} {adr} [set | unset | del] ...

   userdb -show {path}

   userdb -show {path} {addr}

   userdb -show -f {file}

   userdb -show -f {file} {addr}

DESCRIPTION

   userdb is a convenient script to individually manipulate entries in
   /etc/courier/userdb. See makeuserdb(8)[1] for a description of its
   contents.  /etc/courier/userdb can always be edited using any text
   editor, but userdb is a convenient way to modify this file from another
   script.

   /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<TAB>field=value|field=value...

   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)[1] 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.

   For example:

       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.

   DISPLAYING /etc/courier/userdb
   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.

   REBUILDING /etc/courier/userdb.dat
   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)[1] command to
   rebuild /etc/courier/userdb.dat for the changes to take effect.

BUGS

   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)[1] command will fail with
   an error message.

FILES

   /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

SEE ALSO

   makeuserdb(8)[1], userdbpw(8)[2]

NOTES

    1. makeuserdb(8)
       [set $man.base.url.for.relative.links]/makeuserdb.html

    2. userdbpw(8)
       [set $man.base.url.for.relative.links]/userdbpw.html



Opportunity


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.



Free Software


Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.



Free Books


The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.



Education


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.


birds banner