Can’t re-open pipe to command substitution (fd 4): No child processes error and solution

Q. I’m running Debian Linux 64 bit server. I’m getting an error which read as follows:
Can’t re-open pipe to command substitution (fd 4): No child processes

How do I fix the problem?

A. This error occurs when Linux server run out of open files maximum limit i.e system cannot create or open a new file due to number of open files reached the maximum limits of files.

To solve this problem just configure the system to accept the more open files. Please see previous faq:

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