coproc

Start a coprocess with bidirectional pipes.

Source: src/execution/builtins.f90:1949-2000, src/execution/coprocess.f90

Synopsis

coproc [NAME] command [args ...]

Description

Starts a command as a background coprocess with its stdin and stdout connected to the shell via pipes. This allows the shell to write to the coprocess's input and read from its output.

If NAME is given, the pipe file descriptors are stored in the array NAME[0] (read fd) and NAME[1] (write fd). If omitted, the default name is COPROC.

A valid name must start with an uppercase letter or _ and contain only uppercase letters, digits, or _.

Usage

# Start a coprocess
coproc cat

# Write to it
echo "hello" >&${COPROC[1]}

# Read from it
read line <&${COPROC[0]}
echo "$line"
# hello

# Named coprocess
coproc MYPROC sed 's/hello/world/'
echo "hello" >&${MYPROC[1]}
read result <&${MYPROC[0]}
echo "$result"
# world

Limits

Up to 10 concurrent coprocesses can be active at once.

Exit Status

See Also

• Pipes - Pipeline syntax
• jobs - List background jobs