From the bash man page: “Each command in a pipeline is executed as a separate process (i.e., in a subshell).” I suppose it would be possible to execute one component of a pipeline in the current shell (i.e. the first, or the last, or maybe one in the middle), it doesn’t play favorites like this: … Read more
Update and caveat: This answer has a troubled past in that I confidently claimed things that turned out not to be true. I believe it has value in its current form, but please help me eliminate other inaccuracies (or convince me that it should be deleted altogether). I’ve substantially revised – and mostly gutted – … Read more
By using $() you are (effectively) creating a subshell. Thus the PIPESTATUS instance you need to look at is only available inside your subshell (i.e. inside the $()), since environment variables do not propagate from child to parent processes. You could do something like this: OUT=$( wget -q “http://budueba.com/net” | tee -a “file.txt”; exit ${PIPESTATUS[0]} … Read more
What you could do, is register the top level shell for the TERM signal to exit, and then send a TERM to the top level shell: #!/bin/bash trap “exit 1” TERM export TOP_PID=$$ function func() { echo “Goodbye” kill -s TERM $TOP_PID } echo “Function call will abort” echo $(func) echo “This will never be … Read more
Use parentheses ()’s to combine the commands into a single process, which will concatenate the stdout of each of them. Example 1 (note that $ is the shell prompt): $ (echo zzz; echo aaa; echo kkk) | sort aaa kkk zzz Example 2: (setopt; unsetopt; set) | sort
I ran into this problem yesterday. The trouble is that you’re doing find $loc -name “*.bsp” | while read. Because this involves a pipe, the while read loop can’t actually be running in the same bash process as the rest of your script; bash has to spawn off a subprocess so that it can connect … Read more
The whole point of a subshell is that it doesn’t affect the calling session. In bash a subshell is a child process, other shells differ but even then a variable setting in a subshell does not affect the caller. By definition. Do you need a subshell? If you just need a group then use braces: … Read more