Mailcap

lastmod 2026-02-18created 2026-02-181 edits

mailcap is a system that defines which program handles files of each MIME type. It was originally created to specify the programs email clients use to open attachments (RFC 1524), and today various programs consult it when looking up MIME handlers.

Configuration files

File path	Description
`/etc/mailcap`	System-wide configuration
`~/.mailcap`	Per-user configuration (takes precedence)

Format

Each line has the form MIME type; command to run, and the file path is substituted for %s.

audio/mpeg; mpv %s
application/pdf; evince %s
image/png; feh %s
text/html; firefox %s

Option fields

In addition to the basic format, extra options can be specified, separated by semicolons (;).

image/gif; feh %s; test=test -n "$DISPLAY"
text/html; lynx %s; needsterminal
application/pdf; evince %s; description="PDF Viewer"

Field	Description
`test=`	Use the entry only when the condition is true
`needsterminal`	Marks the program as requiring a terminal
`copiousoutput`	Produces a large amount of output, so it is displayed through a pager
`description=`	Description of the entry
`compose=`	Command used to create a file of that MIME type
`edit=`	Command used to edit a file of that MIME type

Related commands

Command	Description
`run-mailcap`	General-purpose command that opens files according to the mailcap configuration
`see`	Alias for `run-mailcap --action=view`
`edit`	Alias for `run-mailcap --action=edit`
`compose`	Alias for `run-mailcap --action=compose`

mailcap vs xdg-open

Item	mailcap	xdg-open
Configuration method	Text file (`/etc/mailcap`)	`.desktop` files + `mimeapps.list`
Main environment	CLI / headless servers	GUI desktop environments
Standard	RFC 1524	freedesktop.org XDG specification
Pros	Simple and intuitive	Integrated with the desktop environment

Favorite site

RFC 1524 - A User Agent Configuration Mechanism For Multimedia Mail Format Information

author Zer0 sitemap