Storing openssl file digest as shell variable?

问题:

I am executing the below command in bash

filehash=`openssl dgst -sha1 $filename`

When I echo $filehash

I get this

SHA1(myfile.csv)= bac9c755bac9709fa8966831d1731dff07e28e6c

How do I only get the hash value stored and not the rest of the string i.e.

bac9c755bac9709fa8966831d1731dff07e28e6c

Thanks

回答1:

Through sed,

filehash=`openssl dgst -sha1 $filename | sed 's/^.*= //'`

It removes all the characters upto the =(equal symbol followed by a space).

回答2:

In a lot of ways with pure Bash, e. g. by truncating string from start up to last space:

filehash="$(openssl dgst -sha1 "$filename")"
filehash="${filehash##* }"

or using possibility to obtain reverse (-r) notation from openssl:

read filehash __ < <(openssl dgst -sha1 -r "$filename")

Obviously awk, sed or any other external utility is overkill here. And please note quotes.

回答3:

Either with sed or awk (if you have them installed):

hash=$(echo $filehash | awk -F '=' '{ print $2 }')

for example.