This command prints an empty line in bash-2.05-alt4: a=\"\"; echo A | read a; echo $a but it should print a line with A. --- --- Strange that adding braces helps, these commands print A: a=\"\"; echo A | { a=\"\"; read a; echo $a; } a=\"\"; echo A | ( a=\"\"; read a; echo $a; ) Reading from the keyboard and not a pipe also works correctly. All the three commands mentioned here work the same right way in zsh.
See /usr/share/doc/bash-2.05/FAQ: E4) If I pipe the output of a command into `read variable\', why doesn\'t the output show up in $variable when the read command finishes? This has to do with the parent-child relationship between Unix processes. It affects all commands run in pipelines, not just simple calls to `read\'. For example, piping a command\'s output into a `while\' loop that repeatedly calls `read\' will result in the same behavior. Each element of a pipeline runs in a separate process, a child of the shell running the pipeline. A subprocess cannot affect its parent\'s environment. When the `read\' command sets the variable to the input, that variable is set only in the subshell, not the parent shell. When the subshell exits, the value of the variable is lost.
