Editing Configuration file (section)

===Unix and Unix-like===
Many different file formats are used on [[Unix]] and [[Unix-like]] operating systems. Even so, there is a strong tradition of using human-editable, plain text formats including simple [[key–value pair]]. Filename extensions of <code>.cnf</code>, <code>.conf</code>, <code>.cfg</code>, <code>.cf</code> or <code>.ini</code> are often used.

Many formats allow [[Comment (computer programming)|comments]], in which case, individual settings can be disabled by [[comment out|prepending with the comment character]]. Often the default configuration files contain extensive internal documentation in the form of comments<ref name=":0">https://opensource.apple.com/source/postfix/postfix-174.2/Postfix.Config/main.cf.default. {{Webarchive|url=https://web.archive.org/web/20170803053000/https://opensource.apple.com/source/postfix/postfix-174.2/Postfix.Config/main.cf.default |date=2017-08-03 }}</ref><ref name=":1">http://opensource.apple.com/source/apache/apache-769/httpd.conf. {{Webarchive|url=https://web.archive.org/web/20200801023500/https://opensource.apple.com/source/apache/apache-769/httpd.conf |date=2020-08-01 }}</ref> and [[man file]]s are also typically used to document the format and options available.

System-wide software often uses configuration files stored in <code>[[/etc]]</code>, while user applications often use a "[[dotfile]]" – a file or directory in the home directory prefixed with a [[full stop|period]], which [[Hidden file and hidden directory#Unix and Unix-like environments|in Unix hides the file or directory]] from casual listing. Since this causes pollution, newer user applications generally make their own folder in the <code>.config</code> directory, a standardized subdirectory of the home directory.

Similar to config files, a [[RUNCOM|run command]] (rc) [[shell script]] can configure a [[shell (computing)|shell]] session. Often, such scripts are named with an <code>rc</code> suffix after the consuming program's name such as <code>.xinitrc</code>, <code>.vimrc</code>, <code>.bashrc</code>, <code>xsane.rc</code>.<ref name="autogenerated1">{{cite web|url=http://www.catb.org/jargon/html/R/rc-file.html |title=rc file |publisher=Catb.org |access-date=2012-02-29}}</ref>

By contrast, [[IBM]]'s [[AIX]] uses an [[Object Data Manager]] (ODM) database to store much of its system settings.