Bash: GNU Parallel with Curl

parallel_curl.sh

# do it once
seq 1 | parallel -n0 "curl http://localhost:3000"

# do it twice
seq 2 | parallel -n0 "curl --header 'Connection: keep-alive' http://localhost:3000"

# do it 4 times, but at 2 a time
seq 10000 | parallel -n0 -j10 "curl --header 'Connection: keep-alive' https://prelive.tripl.de"
```

# you can also put all your commands into a file
echo "ls\nls" > somefile
cat somefile | parallel

# finally, just straight command line parameters
parallel echo ::: a b c

# by default, it runs as many jobs in parallel as there are cores in your computer

# if you try and set more jobs than there are cores, they will be concurrent, but 
# they will only ever be parallel up to your core count

# for httpie use the --ignore-stdin flag, or else it gets mixed up
# seq 1 | parallel -n0 "http --ignore-stdin POST http://httpbin.org/post url=http://google.com/"