multicurl attempt

gistfile1.txt

#!/bin/bash

FIFO=$(mktemp /tmp/multicurl.XXXXX)

echo FIFO=$FIFO
for arg in "$@"
do
  curl $arg > $FIFO &
done

# this doesn't work as:
# - both are noisy
# - both streams overlap (want line buffered)
# - ctrl-c leaves the curls running in background

To avoid interleaving you might need something like:

for arg in "$@"; do
    curl | while read -r line; do printf "%s\n" "$line" >"$FIFO"; done &
done

while true; do
    cat "$FIFO"
done

Terminating when all the curl processes have finished is not solved.

# Assuming bash
pids=()
for arg in "$@"; do
    curl | while read -r line; do printf "%s\n" "$line" >"$FIFO"; done &
    pids+="$!"
done

trap 'for pid in "${PIDS}"; do kill $pid; done' EXIT

while true; do cat "$FIFO"; done

# easier in Perl probably?
use strict;
use warnings;

my @FH = map {
    open (my $FH, '-|', 'curl', '-s', '-k', $_);
    $FH;
} @ARGV;

while (1) {
    my @lines = grep defined, map scalar <$_>, @FH or last;
    print @lines;
}