diff --git a/README.md b/README.md
index 993057d..898a230 100644
--- a/README.md
+++ b/README.md
@@ -1,45 +1,52 @@
 ### ffx.sh
+
 quickly apply audio effects using ffmpeg <br>
 
-
-
 <pre>
-
 supports
--mp3, wav, flac, ogg, opus, m4a, aac, and mka
-
+-mp3, wav, flac, ogg, opus, m4a, aac, mka
 
 features
 -bass, treble, volume, distortion
 -trim audio
--tempo change with pitch preserving
--pitch change
+-tempo change with pitch preservation
+-pitch change with duration preservation
 
+example usage
+./ffx.sh bass audio.mp3 10 1
 
-example usage: ./ffx.sh bass audio.mp3 10 1
-
-helper commands:
+helper commands
 ffbass "audio.mp3" 10 1 bassboosted.mp3
 bass audio.mp3 10 1
 bassboost audio.mp3
-
-
 </pre>
 
 ---
 
-
 <pre>
-
 help docs
 
 help and version
 ./ffx.sh --help
 ./ffx.sh --version
 
+commands
+./ffx.sh bass INPUT PERCENT [FINE_DB] [OUTPUT]
+./ffx.sh treble INPUT PERCENT [FINE_DB] [OUTPUT]
+./ffx.sh volume INPUT DB [OUTPUT]
+./ffx.sh distort INPUT [DRIVE_0_TO_10] [OUTPUT]
+./ffx.sh trim INPUT START_SECONDS [END_SECONDS] [OUTPUT]
+./ffx.sh tempo INPUT SPEED_0.125_TO_8 [OUTPUT]
+./ffx.sh pitch INPUT SEMITONES_-36_TO_36 [OUTPUT]
+
 bass and treble
-./ffx.sh bass song.mp3 25 bass-song.mp3
-./ffx.sh treble song.mp3 20 bright-song.mp3
+./ffx.sh bass song.mp3 25 1 bass-song.mp3
+./ffx.sh treble song.mp3 20 1 bright-song.mp3
+
+33 = 16.5 db
+66 = 33 db
+100 = 50 db
+fine_db is added or subtracted afterward.
 
 volume
 ./ffx.sh volume song.mp3 -6 quieter-song.mp3
@@ -50,7 +57,7 @@ distortion
 
 trim audio
 ./ffx.sh trim song.mp3 10 30 clip.mp3
-./ffx.sh trim podcast.mp3 30 no-intro.mp3
+./ffx.sh trim podcast.mp3 30 60 no-intro.mp3
 
 tempo with pitch preservation
 ./ffx.sh tempo lecture.mp3 1.5 fast-lecture.mp3
@@ -66,57 +73,76 @@ convert while editing
 automatic output filename
 ./ffx.sh bass song.mp3 30
 
+input:  star.mp3
+output: star333033.mp3
 </pre>
-<pre>
 
+<pre>
 install helper commands
 ./ffx.sh --add-helper-cmd
 
+remove helper commands
+./ffx.sh --remove-helper-cmd
+
 cmd helpers
-  
   ffbass   INPUT PERCENT [FINE_DB] [OUTPUT]
   fftreble INPUT PERCENT [FINE_DB] [OUTPUT]
-
-    33 = 16.5 dB (half of 33 dB)
-    66 = 33 dB
-    100 = 50 dB
-    FINE_DB is added/subtracted afterward.
-
-  ffvolume  INPUT DB [OUTPUT]
+  ffvolume INPUT DB [OUTPUT]
   ffdistort INPUT [DRIVE_0_TO_10] [OUTPUT]
-  fftrim    INPUT START_SECONDS [END_SECONDS] [OUTPUT]
-  fftempo   INPUT SPEED_0.125_TO_8 [OUTPUT]       # preserves pitch
-  ffpitch   INPUT SEMITONES_-36_TO_36 [OUTPUT]    # preserves duration
+  fftrim   INPUT START_SECONDS [END_SECONDS] [OUTPUT]
+  fftempo  INPUT SPEED_0.125_TO_8 [OUTPUT]
+  ffpitch  INPUT SEMITONES_-36_TO_36 [OUTPUT]
 
 defaults
-  output uses the source extension and a unique suffix.
-  use an explicit filename ending in .mp3 for MP3 output.
+-output uses the source extension and a unique suffix.
+-use an explicit filename ending in .mp3 for mp3 output.
 
 examples
-  ffbass "audio.mp3" 33 2
-  ffbass "song.wav" 33 2 "bass.mp3"
-  fftreble "song.flac" 66 -4 "treble.flac"
-  ffvolume "song.mp3" -3
-  ffdistort "song.wav" 4 "distorted.mp3"
-  fftrim "song.mp3" 12.5 48 "clip.mp3"
-  fftempo "song.mp3" 0.5 "slow.mp3"
-  ffpitch "song.mp3" -3 "lower.mp3"
-
+ffbass "audio.mp3" 33 2
+ffbass "song.wav" 33 2 "bass.mp3"
+fftreble "song.flac" 66 -4 "treble.flac"
+ffvolume "song.mp3" -3
+ffdistort "song.wav" 4 "distorted.mp3"
+fftrim "song.mp3" 12.5 48 "clip.mp3"
+fftempo "song.mp3" 0.5 "slow.mp3"
+ffpitch "song.mp3" -3 "lower.mp3"
+</pre>
 
+<pre>
 zsh helpers
 
-usages:
-  bass "song.mp3" 33 2
-  treble "song.flac" 66 -4
-  volume "song.mp3" -3
-  distort "song.wav" 4
-  trim "song.mp3" 12.5 48
-  tempo "song.mp3" 0.5
-  pitch "song.mp3" -3
+install
+bash install-ffx-zsh.sh
 
-presets:
-  bassboost audio.mp3
-  grunge audio.mp3 
+the installer
+-prompts for the directory containing ffx.sh
+-auto-finds ffx.sh when pressing enter
+-ensures ffx.sh is executable
+-validates ffx.sh
+-creates ~/.ffx.zshrc.snippet
+-adds source "$HOME/.ffx.zshrc.snippet" to ~/.zshrc if missing
 
+reload zsh
+source ~/.zshrc
 
+usages
+bass "song.mp3" 33 2
+treble "song.flac" 66 -4
+volume "song.mp3" -3
+distort "song.wav" 4
+trim "song.mp3" 12.5 48
+tempo "song.mp3" 0.5
+pitch "song.mp3" -3
+
+presets
+bassboost audio.mp3
+grunge audio.mp3
+
+preset values
+bassboost INPUT = bass INPUT 5 1
+grunge INPUT = distort INPUT 2
+
+custom output
+bassboost audio.mp3 bassboosted.mp3
+grunge audio.mp3 grunge.mp3
 </pre>
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