Filter output of command in Linux

Question

How do I print out just the hashsum and file name with sha256sum command? I want Hashsum and just the filename instead of the full path.

Command:

sha256sum /mydir/someOtherDir/file.txt

Output:

123Hashsum /mydir/someOtherDir/file.txt

Desired Output:

123Hashsum file.txt

The easiest way to get your expected result might be to use cd /mydir/someOtherDir/; sha256sum file.txt instead of sha256sum /mydir/someOtherDir/file.txt — Aaron
– Aaron, Commented May 3, 2019 at 9:24
There are ways to do this, for instance by changing the working directory or post-processing sha256sum's output. However, you may want to explain why you want to do this. If you want to use an aliased version of the command for better readability that's fine. But if you want to parse your expected output it wouldn't make sense to post-process the original output just so that you parse it a second time after that. Also: Do you need support for multiple files in different directories, for instance sha256sum /dir1/file1 /dir2/dir3/file2? — Socowi
– Socowi, Commented May 3, 2019 at 9:25
I was testing some C code to get hashsums of files. I know it's better to use C libraries like openssl, but this was just a small hack for a workaround using a system call. The files coming in aren't necessarily in the corresponding folder. — kilamondrow
– kilamondrow, Commented May 3, 2019 at 9:40

John Kugelman · Accepted Answer · 2019-05-03 10:24:38Z

1

You can read the output into variables

read -r sha file < <(sha256sum /mydir/someOtherDir/file.txt)

Then you can read just the filename with basename

echo "$sha" "$(basename "$file")"

John Kugelman

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answered May 3, 2019 at 9:29

fancyPants

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1 Comment

or echo "$sha ${file##*/}" in bash, but not sh

nullPointer · Accepted Answer · 2019-05-03 12:00:24Z

0

You can try piping to sed as below (works with absolute paths only) :

sha256sum /mydir/someOtherDir/file.txt | sed 's:/.*/::'

answered May 3, 2019 at 12:00

nullPointer

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