man pages section 4: File Formats
    
U
 
 ufs, format -- dir_ufs ( Index Term Link )
 
 ufsdump -- incremental dump format ( Index Term Link )
 
 updaters - configuration file for NIS updating ( Index Term Link )
 
 user-preference variables files for AT&T FACE -- environ ( Index Term Link )
 
 utmp -- utmp and wtmp database entry formats ( Index Term Link )
 
 utmp and wtmp database entry formats -- utmp ( Index Term Link )
 
 utmp and wtmp database entry formats -- wtmp ( Index Term Link )
 
 utmpx -- utmpx and wtmpx database entry formats ( Index Term Link )
 
 utmpx and wtmpx database entry formats -- utmpx ( Index Term Link )
 
 utmpx and wtmpx database entry formats -- wtmpx ( Index Term Link )