Wait for key in shell script that may get piped to /bin/bash Consider the following shell script echo foo; read; echo bar Running `bash my_script` outputs 'foo', waits for the return key and outputs 'bar'. While this works fine running it that way, it doesn't work anymore if piped to /bin/bash: $ echo 'echo foo;read;echo bar'|bash directly outputs 'foo' and 'bar' without waiting for a key press. Why doesn't read work anymore when using it this way? Is there any way to rewrite the script in a way it works as file script file as well as a script string piped to /bin/bash?

This is really easy, actually, First, you need to set aside your stdin in some remembered descriptor:


exec 9<&0


There. You've made a copy. Now, let's pipe our commands at our shell.


echo 'echo foo; read <&9; echo bar' | bash


...well, that was easy. Of course, we're not really done yet. We should clean up.


exec 9<&-


Ok, now we're done.

But we can avoid the cleanup if we just group our commands a little...


{ echo 'echo foo; read <&9; echo bar' | bash; } 9<&0


The descriptor only survives as long as its assigned compound command does in that case.