Linuxでディスプレイを録画したいとき、コマンドからだとrecordmydesktopというコマンドを実行することで画面の録画を行うことができます。
また、gtk-recordmydesktopというGUIアプリケーションもあり、こちらを使えば範囲指定なども簡単にできて、初心者にはオススメです。
しかし、細かく設定したい人にとっては、コマンドラインから実行するニーズもあるかと思いますので、zshにおける補完関数書いてみました。
基本的には、helpとmanページをコピペしながら作ったものですが、何かの役に立てば幸いです。
オプションの細かい説明はhelpを参照してください。
また何か改善点などあれば、コメントいただければと思います。

dotfiles/_recordmydesktop at master · ssh0/dotfiles

# recordmydesktop completion                                               {{{
# ------------------------------------------------------------------------------

_recordmydesktop() {
  local curcontext="$curcontext" diropts prev numopts
  typeset -A opt_args
  numopts="-x|-y|--channels|--freq|--buffer-size|--ring-buffer-size|--delay"

  # Set the default saving directory
  ddir="$HOME/Videos"

  prev=$words[CURRENT-1]
  if [[ ${prev} =~ ${numopts} ]]; then
    _arguments "*: :"
  elif [[ ${prev} == "-o" ]]; then
    _path_files -W ddir
  elif [[ ${prev} == "--rescue" ]]; then
    _path_files
  elif [[ ${prev} == "--workdir" ]]; then
    _path_files -/
  elif [[ ${prev} == "--width" ]]; then
    _arguments "*: :(1920 1680 1440 1280 1152 1024 800 720 640)"
  elif [[ ${prev} == "--height" ]]; then
    _arguments "*: :(1080 1050 1024 960 900 864 768 600 576 480)"
  elif [[ ${prev} == "--dummy-cursor" ]]; then
    _arguments "*: :(black white)"
  elif [[ ${prev} == "--fps" ]]; then
    _arguments "*: :(60 30 10)"
  elif [[ ${prev} == "--v_quality" ]]; then
    _arguments "*: :(0 63)"
  elif [[ ${prev} == "--v_bitrate" ]]; then
    _arguments "*: :(45000 2000000)"
  elif [[ ${prev} == "--s_quality" ]]; then
    _arguments "*: :(-1 0 5 10)"
  elif [[ ${prev} == "--pause-shortcut" ]]; then
    _arguments "*: :'Control+Mod1+p'"
  elif [[ ${prev} == "--stop-shortcut" ]]; then
    _arguments "*: :'Control+Mod1+s'"
  else
    _arguments -s -S\
      '(--help)--help[Print help summary and exit.]: :' \
      '(--version)--version[Print program version and exit.]: :' \
      '(--print-config)--print-config[Print info about options selected during compilation and exit.]' \
      '(--windowid)--windowid[id of window to be recorded.]' \
      '(--display)--display[Display to connect to.]' \
      '(-x)-x[Offset in x direction.]' \
      '(-y)-y[Offset in y direction.]' \
      '(--width)--width[Width of recorded window.]' \
      '(--height)--height[Height of recorded window.]' \
      '(--dummy-cursor)--dummy-cursor[Draw a dummy cursor, instead of the normal one.Value of color can be \"black\" or \"white\".]' \
      '(--no-cursor)--no-cursor[Disable drawing of the cursor.]' \
      '(--no-shared)--no-shared[Disable usage of MIT-shared memory extension (Not Recommended).]' \
      '(--full-shots)--full-shots[Take full screenshot at every frame(Not recomended!).]' \
      '(--follow-mouse)--follow-mouse[When this option is enabled, the capture area follows the mouse cursor.]' \
      '(--quick-subsampling)--quick-subsampling[Do subsampling of the chroma planes by discarding extra pixels.]' \
      '(--fps)--fps[A positive number denoting desired framerate.]' \
      '(--channels)--channels[A positive number denoting desired sound channels in recording.]' \
      '(--freq)--freq[A positive number denoting desired sound frequency.]' \
      '(--buffer-size)--buffer-size[A positive number denoting the desired sound buffer size(in frames, when using ALSA or OSS).]' \
      '(--ring-buffer-size)--ring-buffer-size[A float number denoting the desired ring buffer size (in seconds,when using JACK only).]' \
      '(--device)--device[Sound device(default hw:0,0 or /dev/dsp, depending on whether ALSA or OSS is used).]' \
      '(--use-jack)--use-jack[Record audio from the specified list of space-separated jack ports.]' \
      '(--no-sound)--no-sound[Do not record sound.]' \
      '(--on-the-fly-encoding)--on-the-fly-encoding[Encode the audio-video data, while recording.]' \
      '(--v_quality)--v_quality[A number from 0 to 63 for desired encoded video quality(default 63).]' \
      '(--v_bitrate)--v_bitrate[A number from 45000 to 2000000 for desired encoded video bitrate(default 45000).]' \
      '(--s_quality)--s_quality[Desired audio quality(-1 to 10).]' \
      '(--rescue)--rescue[Encode cache data from a previous session, into an Ogg/Theora+Vorbis file.]' \
      '(--no-wm-check)--no-wm-check[When a 3d compositing window manager is detected the program will function as if the --full-shots option has been specified.]' \
      '(--no-frame)--no-frame[If you do not wish the frame to appear, use this option.]' \
      '(--pause-shortcut)--pause-shortcut[Shortcut that will be used for pausing or unpausing the recording. Default is Control+Mod1+p (Mod1 usually corresponds to left Alt).]' \
      '(--stop-shortcut)--stop-shortcut[Shortcut that will be used to stop the recording. Default is Control+Mod1+s.]' \
      '(--compress-cache)--compress-cache[Image data are cached with a light compression.]' \
      '(--workdir)--workdir[Location where a temporary directory will be created to hold project files(default /tmp).]' \
      '(--delay)--delay[Number of secs(default),minutes or hours before capture starts(number can be float).]' \
      '(--overwrite)--overwrite[If there is already a file with the same name, delete it.]'
  fi
}

compdef _recordmydesktop recordmydesktop

# ---------------------------------------------------------------------------}}}