Answer by Steven D for How can I get a base64 encoded shaX on the cli?

I'm not completely sure I understand what you want, but I think something like the following should work:

$ echo -ne "$(echo -n "message" | sha1sum | cut -f1 -d" " | sed -e 's/\(.\{2\}\)/\\x\1/g')" | base64

Basically, I take the hex output, use sed to make it a string of escaped hex values, and then use echo -en to echo the bytes into base64.

We can confirm that the final output corresponds to the same hash with the following exercise:

$ echo -n "message" | sha1sum 
6f9b9af3cd6e8b8a73c2cdced37fe9f59226e27d  -

$ echo -ne "$(echo -n "message" | sha1sum | cut -f1 -d" " | sed -e 's/\(.\{2\}\)/\\x\1/g')" | base64
b5ua881ui4pzws3O03/p9ZIm4n0=

$ echo -n "b5ua881ui4pzws3O03/p9ZIm4n0=" | base64 -d | xxd
0000000: 6f9b 9af3 cd6e 8b8a 73c2 cdce d37f e9f5  o....n..s.......
0000010: 9226 e27d                                .&.}

Visual inspection shows that our base64 value matches the original hex. Note that if you use hexdump rather than xxd you may have to play with the format settings a bit to get the output you expect.