>

Work With Caesar Ciphers Using caesar

Decrypt a shift cipher automatically or with a known rotation.

LinuxTerminalscriptingsecurityLow risk
Run echo "khoor zruog" | caesar 3 to shift the text back by three positions.

01Command

Command
$ echo "khoor zruog" | caesar 3

02What it does

caesar reads standard input and either guesses the rotation from English letter frequency or uses a rotation you supply. It is a small puzzle-solving and teaching tool for classical cryptography, and doubles as a quick shift filter.

03Risk

RiskLow risk
Requirementssudo apt install bsdgames
!Warning: Frequency analysis only works on longer English text; short messages may be decoded with the wrong rotation.

04Undo

✓No undo needed — this command does not change persistent state.

05Sources

  • Debian package: bsdgames
    Debian · vendor-doc · 2026-09-20
    Evidence: Installs bsdgames, which includes caesar, a Caesar-cipher tool.
  • caesar(6) — Debian manpage
    Debian · technical · 2026-09-20
    Evidence: Documents caesar, which decrypts shift ciphers using English letter frequency.

Last verified: 2026-09-20 · Category: Developer

06Related solutions

Create an SSH key pair with ssh-keygen (Ed25519)
LinuxTerminaldevelopersecurity

Generate a modern Ed25519 public/private key pair in ~/.ssh for authenticating to servers and Git platforms without passwords.

Low risk ✓ 2026-09-17
Change file permissions with chmod
LinuxFilesTerminalsecurity

Add or remove read, write, and execute permission for the owner, group, or others using symbolic or octal modes.

Medium risk ✓ 2026-09-17
Update and upgrade packages on Debian/Ubuntu with apt
LinuxsystemTerminal

Refresh the package index from all configured repositories, then install newer versions of every upgradable package.

Medium risk ✓ 2026-09-17