In terminal (bash) the following works fine:
cat <(echo "hello")
But if I do:
sh -c 'cat <(echo "hello")'
I get
sh: 1: Syntax error: "(" unexpected
Can you explain the reason why?
Btw, my overall aim is to write this command in a shell script:
watch -n 1 'cat <(iptables -L INPUT) <(iptables -L FORWARD)'
but it won't work, the reason seems to be the above problem.
sh is often dash not bash (see man sh). dash doesn't do process substitution, only POSIX stuff.
You'll need to do:
bash -c 'cat <(echo "hello")'
ksh & zsh can do process substitution too.
With your example, you can simply do:
watch -n 1 'iptables -L INPUT; iptables -L FORWARD'
no need for an advanced shell or process subtitution.
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