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Comment by yuchi | Hacker News Reader

Do someone know how to run a command for every line emitted in a unix pipe? I tried the oneliner in the linked story using Mac OS X’s `say`, but it doesn’t work with pipes.

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In a typical UNIX fashion, there's a program that runs programs:

  ping 127.0.0.1 | sed -e 's/.*/ping/' | xargs -d'\n' -n1 say

-d is a GNU extension, won't work on OSX (short of having installed and running GNU xargs), and it's not needed either in this case.

And `sed -e <command>` is redundant, `-e` is used to specify multiple commands.

xargs -n1 (-n is so it executes the command for each input)

You'll also need sed -l to limit buffering.

    ping <host> | sed -l 's/.*/ping/' | xargs -n1 say

perfect!

  cat input |while read a; do do_something_with $a; done

thank you so much!

ping goodhost | sed -l 's/.*/ping/' | while read line; do echo $line | say; done

You might want to use "--unbuffered" flag in sed execution.

that option appears to be gnu-specific. -l should make it line-buffered

Note that -l is also an extension, just a BSD one.

The only options in POSIX sed are -e, -f and -n (and -e is usually cargo-culted by people who want -E. -E being a BSD extension enabling extended regular expressions — -r in GNU sed)

Bit of a tangent, but using the voice "Tom" on OS X, saying "ping" says "pling" instead. Fine with other voices but rather curious.

For some fun: https://github.com/mpdehaan/ansible-and-juliet

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