You download a binary from GitHub and the release page lists a SHA-256 checksum. To verify it, you open Terminal, type shasum -a 256 ~/Downloads/file.tar.gz, wait for it to compute, then manually compare two 64-character hex strings side by side. One wrong character and you cannot tell if the file is corrupted or you just misread the hash.
Or you need to generate an MD5 hash of a string — maybe for a cache key, a Gravatar URL, or a legacy API that still uses MD5 signatures. The command is md5 -s "text" on macOS but md5sum on Linux. Small differences, but enough to slow you down when you switch between systems.
Hashing in Terminal: It Works, Barely
macOS ships with md5, shasum, and openssl dgst, covering most algorithms. But each tool has its own syntax. md5 uses -s for string input. shasum uses -a to select the algorithm. openssl dgst requires -sha256 or -md5 as a flag. There is no single command that lets you pick an algorithm and hash a string without consulting the man page.
For developers who occasionally need a quick hash, the cognitive overhead of remembering these variations is disproportionate to the simplicity of the task.
Generate Hashes With One Paste
Bellows includes a hash generator that supports MD5, SHA-1, SHA-256, SHA-384, SHA-512, and other common algorithms. Type or paste your input, select an algorithm, and the hash appears instantly. No flags to remember, no syntax to look up.
Verifying Downloads
When a release page provides a checksum, you want to compare it against the file you downloaded. Generating the hash in a visual tool makes the comparison easier than eyeballing two strings in a terminal window — especially for 64-character SHA-256 hashes.
API Signatures and Cache Keys
Some APIs require HMAC or hash-based signatures for request authentication. Others use MD5 or SHA hashes as cache keys or content identifiers. Being able to quickly generate a hash of a request body or a string lets you verify your implementation against expected values during debugging.
Offline and Private
Hashing input might contain sensitive data — passwords, API secrets, internal identifiers. Bellows runs entirely on your Mac with no network access, so nothing you hash ever leaves your machine.