knjname · December 21, 2015 06:59
diff --git a/ABashSubShellPitfall.sh b/ABashSubShellPitfall.sh
 #!/bin/bash

 # bash executes this incorrectly.
 # On the other hand zsh executes this correctly.
 # Because bash spawns a sub-shell inside while-do loop meanwhile zsh doesn't it.
 declare -i sum
 seq 0 10 | while read num ; do
  let sum+=$num
 done

 # bash => nothing
 # zsh => 55
 echo $sum
	#!/bin/bash

	# bash executes this incorrectly.
	# On the other hand zsh executes this correctly.
	# Because bash spawns a sub-shell inside while-do loop meanwhile zsh doesn't it.
	declare -i sum
	seq 0 10 \| while read num ; do
	let sum+=$num
	done

	# bash => nothing
	# zsh => 55
	echo $sum