coproc

Bash builtin for creating interactive asynchronous subshells. More information: https://www.gnu.org/software/bash/manual/bash.html#Coprocesses.

• Run a subshell asynchronously:
  coproc { {{command1; command2; ...}}; }
• Create a coprocess with a specific name:
  coproc {{name}} { {{command1; command2; ...}}; }
• Write to a specific coprocess stdin:
  echo "{{input}}" >&"${{{name}}[1]}"
• Read from a specific coprocess stdout:
  read {{variable}} <&"${{{name}}[0]}"
• Create a coprocess which repeatedly reads stdin and runs some commands on the input:
  coproc {{name}} { while read line; do {{command1; command2; ...}}; done }
• Create a coprocess which repeatedly reads stdin, runs a pipeline on the input, and writes the output to stdout:
  coproc {{name}} { while read line; do echo "$line" | {{command1 | command2 | ...}} | cat /dev/fd/0; done }
• Create and use a coprocess running bc:
  coproc BC { bc --mathlib; }; echo "1/3" >&"${BC[1]}"; read output <&"${BC[0]}"; echo "$output"