I set variables in a loop that's in a pipeline. Why do they disappear after the loop terminates? Or, why can't I pipe data to read?

I set variables in a loop that's in a pipeline. Why do they disappear after the loop terminates? Or, why can't I pipe data to read? In most shells, each command of a pipeline is executed in a separate SubShell. Non-working example: # Works only in ksh88/ksh93, or zsh or bash 4.2 with lastpipe enabled # In other shells, this will print 0 linecount=0 printf '%s\n' foo bar | while IFS= read -r line d

[kiririmode]

pipeの後段コマンドはsubshellで立ち上がるので後段にforやwhileを配置するとき注意。process substitutuinをリダイレクトしてwhileに渡すほうがスムーズ

[takahiroki]

while read line へパイプで接続すると、その中の while 文が subshell 実行されてしまう問題。基本的に、回避不可能っぽい。 -> pipeline の要素自体を丸々 subshell かして、そこにいろいろ押し込める、が回避策っぽい。