And here's the set of complementary commands

ssb-blob-path.fish

ssb-path-blob.fish

$ ssb-blob-path.fish '&O2V61izsKwCsDJnuI43Gb39FTUxDNY0lsFM7gAKNCKI=.sha256'
/home/kas/.ssb/blobs/sha256/3b/657ad62cec2b00ac0c99ee238dc66f7f454d4c43358d25b0533b80028d08a2
$ ssb-path-blob.fish ~/.ssb/blobs/sha256/3b/657ad62cec2b00ac0c99ee238dc66f7f454d4c43358d25b0533b80028d08a2
&O2V61izsKwCsDJnuI43Gb39FTUxDNY0lsFM7gAKNCKI=.sha256

Requirements

• fish (only tested with v2.7.1)
• base64 (coreutils)
• xxd