This command allows you to disable/enable fall damage. Use /gamerule doFallDamage 0 to disable and 1 to re-enable. One downside is that Jump Boost Effects do not work. Generated using MrGarretto's Multiple Command Generator! If any bugs, tell me in comments! V2: Fixed Lava Bug.
How to install
How to import this command into your world
First, you must give yourself a command block (If you are on a server, you must be 'OP'ed, and have access to /gamemode 1)
To get a command block, type
/give @p command_block in the chat.
Once you have a command block, right click it to open it's GUI.
Now, you must copy and paste the command from your browser into the game. Select the entire command from below, then right click and press 'copy'.
Next, go back to your minecraft world, and paste the command you just copied into the command block. There are a few different keys that may be used to do this, depending on your keyboard. The most common ones are 'CTRL + V', 'COMMAND + V', or 'STRG + V'
Finally, you can press done to exit the GUI, and execute the command block by powering it with a redstone block, a lever, or any thing you can get your grubby hands on. Just make sure you don't place it on top of the command block, or the machine will not be installed!
Show source commands
INIT:/summon ArmorStand ~ ~100 ~ {CustomName:Gamerule1,NoGravity:1,Invisible:1}
INIT:/tellraw @a {text:"Fall Damage Gamerule command made by ",color:green,extra:[{text:"sumdumdude",color:gold}]}
INIT:/tellraw @a {text:"Made using MrGarretto's Command Generator! Check out their channel!",color:light_purple}
INIT:/tellraw @a {text:"Do /gamerule doFallDamage 0 to disable fall damage",color:gold}
INIT:/scoreboard objectives add doFallDamage dummy
INIT:/scoreboard players set @e[name=Gamerule1] doFallDamage 1
/gamerule doFallDamage
/stats block ~ ~ ~-2 set QueryResult @e[name=Gamerule1] doFallDamage
/execute @e[name=Gamerule1,score_doFallDamage=0] ~ ~ ~ effect @a jump_boost 1 255 true
/execute @e[score_doFallDamage=0] ~ ~ ~ execute @a ~ ~ ~ detect ~ ~ ~ lava -1 effect @p jump_boost 0
/summon FallingSand ~ ~1 ~ {Block:redstone_block,Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:fill ~ ~0 ~1 ~ ~-14 ~1 redstone_block},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:setblock ~ ~3 ~1 stone},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:setblock ~ ~4 ~ command_block 0 replace {Command:fill ~ ~2 ~ ~ ~-18 ~1 air}},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:/scoreboard players set @e[name=Gamerule1] doFallDamage 1},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:/scoreboard objectives add doFallDamage dummy},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:/tellraw @a {text:"Do /gamerule doFallDamage 0 to disable fall damage",color:gold}},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:/tellraw @a {text:"Made using MrGarretto's Command Generator! Check out their channel!",color:light_purple}},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:/tellraw @a {text:"Fall Damage Gamerule command made by ",color:green,extra:[{text:"sumdumdude",color:gold}]}},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:/summon ArmorStand ~ ~100 ~ {CustomName:Gamerule1,NoGravity:1,Invisible:1}},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:/summon FallingSand ~2 ~ ~-1 {Block:command_block,TileEntityData:{Command:/execute @e[name=Gamerule1,score_doFallDamage=0] ~ ~ ~ effect @a jump_boost 1 255 true},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:/gamerule doFallDamage},Time:1,}}},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:/summon FallingSand ~2 ~ ~1 {Block:command_block,TileEntityData:{Command:/execute @e[score_doFallDamage=0] ~ ~ ~ execute @a ~ ~ ~ detect ~ ~ ~ lava -1 effect @p jump_boost 0},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:/stats block ~ ~ ~-2 set QueryResult @e[name=Gamerule1] doFallDamage},Time:1,}}},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:gamerule commandBlockOutput false},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:fill ~2 ~-2 ~ ~2 ~0 ~ redstone_block},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:setblock ~2 ~-1 ~-1 command_block 0 replace {Command:fill ~ ~ ~1 ~ ~2 ~1 stone 0 replace redstone_block}},Time:1,Riding:{id:FallingSand,Block:command_block,TileEntityData:{Command:setblock ~2 ~ ~1 command_block 0 replace {Command:fill ~ ~ ~-1 ~ ~2 ~-1 redstone_block 0 replace stone}},Time:1,Riding:{id:FallingSand,Block:stone,Time:1}}}}}}}}}}}}}}}}}