Hello,
I've found these commands in https://help.ubuntu.com/community/LiveCDCustomization:
But I don't understand these commands, even after reading their manuals.
Someone please explain for me.
Sorry for my English.
Thank you very much!

Find files of type regular and separate them with NULs (to account for spaces and such) and for some bizarre reason, pipe them into sudo. (Ubuntu. *shrug*) Regardless, xargs will build a command list out of them (also expecting NUL separators) and md5sum them. Grep will exclude any files named 'isolinux/boot.cat' and some more craziness with sudo and then tee will display the list to the terminal and write the md5sums to the file md5sum text. (AFAICT, none of the sudos make any sense, especially as find would need to have root perms to go looking through root-read-only dirs or whatever.)

That's the gist, I think.

-- Oh, and welcome to LQ!

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Yeah, the find '-print0' and xargs '-0' are special options that allow these two programs to communicate using the NUL terminators instead of whitespace terminators, which makes the command work on file names that have spaces. '-type f' means find files. Note that grep '-v' inverts matches, so you can think of it as anything matched is removed instead of kept. tee just reads from stdin and outputs to both stdout and a file.

1 members found this post helpful.

Thank you slakmagik and H_TeXMeX_H,
I understand now .
This forum is really helpful!

Seems an overly complicated way of doing things. md5sum will happily take imput from stdin, so the xargs are also completely unnecessary and the whole thing can be simplified to something along the lines of.

sudo "find . -type f ! -path './isolinux/boot.cat' | md5sum | tee md5sum.txt"