siddharth ravikumar

2fa: add -mv flag to rename key name

4

Summary of changes: - Add `encodeKey` function. - Add `(*Keychain) filePath` method. - Add `-mv` flag to rename key name.

The `has(key)' method returns True if 'key is present in the db; False otherwise. Also wrote the test method -- testHas() -- in tests.py, to test the `has(key)' method. modded...

activate.fish: update fish major version check

1

Use fish's [`string sub`][ss] command to get fish's major version from `$FISH_VERSION`. The [`head`][head] program in OpenBSD does not have the `-c` flag. Addresses #2892. [head]: https://man.openbsd.org/head [ss]: https://fishshell.com/docs/current/cmds/string.html#sub-subcommand

Currently, activate.fish uses: ```shell echo $FISH_VERSION | head -c 1 ``` to get fish's major version, which fails on OpenBSD as the [`head`][man-head] in OpenBSD does not have a `-c`...