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bashshellcurlxargs

How do I ignore stdin with `xargs`?

I'm using xargs + seq to run a command several thousand times in parrallel.

e.g. running curl 10,000 times with 20 parrallel processes:

seq 1 10000 | xargs -n1 -P20 curl "https://www.example.com/foo"

However xargs is appending the output of stdin to the command it runs (which is what it's designed to do by default). So it ends up effectively running:

curl "https://www.example.com/foo" 1
curl "https://www.example.com/foo" 2
curl "https://www.example.com/foo" 3
curl "https://www.example.com/foo" 4
...

which causes my curl command to error out.

How can I have xargs "ignore" the stdin value here and just output a null/empty value?

I tried a for loop instead but that doesn't run the statements in parallel, which I require.

I also tried formatting the seq as empty strings (seq -f'' 1 10000) which outputs 10,000 blank lines correctly, but xargs ignores this blank input and never runs any commands.

Thanks!

Solution

  • With xargs -I {} you can place the stdin with another {} where you want. If you do not position it in the command the stdin is ignored.