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Processing Text with Linux Shell - Part 1

Shamil on July 27, 2018

Into the world of sed If you are using any *nix systems on a daily basis, chances are you are already familiar with, or at least you hav...
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Rémi Lavedrine

Good guide.
I love using sed for modifying text. It is very useful for Security testing to modify files very quickly.
You must definitely learn how to use sed and grep commands.
It will save you a lot of times.

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kip

Good guide!

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Mathieu PATUREL

sed -i.bak '12,30d' file_name

this is a very nice trick! Thanks!

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kip • Edited

If you ever use vi / vim, this command also works and other commands too.

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p-mcgowan

IIRC on mac sed -i behaves differently - The default is not GNU sed. I believe you can brew it to get the good one

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Shamil

Hi. I have never used any mac. Would you kindly provide details of sed -i behavior so I can update this article accordingly?

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Ben Sinclair • Edited

BSD sed expects -i to take a file extension so it can save a backup.

Instead of using this:

sed -i YOUR_COMMANDS_HERE foo.txt

you can use something like the following, which will make a backup file and then immediately delete it if the command succeeded:

sed -i.bak YOUR_COMMANDS_HERE -- foo.txt && rm -- "foo.txt.bak"

That looks a little nasty, but it's portable; GNU sed's -i also takes a file extension as an optional argument.

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sotondolphin

nice article. many tricks learnt

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Andrey Ramnikov

Very nice tutorial.

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Will

Great post!
I love to use this funky site for more fun with sed: grymoire.com/Unix/Sed.html