mandb
creates and updates the manual page index caches
TLDR
Update man page database
$ mandb
Update single entry$ mandb --filename [path/to/file]
Create database from scratch$ mandb --create
Process user databases only$ mandb --user-db
Don't purge obsolete entries$ mandb --no-purge
Test man pages validity$ mandb --test
SYNOPSIS
mandb [options] [manpath]
DESCRIPTION
mandb creates and updates the manual page index caches. These caches are used by man and apropos to quickly find manual pages. It scans the manual page directories and builds a database of page names and descriptions.
PARAMETERS
--filename FILE
Update single file entry-c, --create
Create database from scratch-u, --user-db
Process only user databases-p, --no-purge
Don't purge obsolete entries-t, --test
Test validity without updating-q, --quiet
Suppress warnings-d, --debug
Print debugging information
CAVEATS
Usually run automatically by package managers. May require root for system-wide databases.