man pages section 2: System Calls
    
U
 
 uadmin — administrative control ( Index Term Link )
 
 ulimit — get and set process limits ( Index Term Link )
 
 umount — unmount a file system ( Index Term Link )
 
 unlink — remove directory entry ( Index Term Link )
 
 unmount a file system — umount ( Index Term Link )
 
 user audit identity, get process audit information — getaudit ( Index Term Link )
 
 user IDs
  set — setuid ( Index Term Link )
  set real and effective — setreuid ( Index Term Link )
 
 utimes — set file access and modification times ( Index Term Link )