Use a recursive function for a bounded calculation.
Bash Scripts: A recursive factorial demonstrates local variables and a clear base case.
set -euo pipefail
factorial() {
local value=$1 previous
if ((value <= 1)); then printf "1\n"; return; fi
previous=$(factorial "$((value - 1))")
printf "%s\n" "$((value * previous))"
}
factorial 5Expected output EXAMPLE
120
Details
Requires Bash 4 or later. Save as snippet.sh and run bash snippet.sh in an empty working directory. A recursive factorial demonstrates local variables and a clear base case.
This uses fixed-width shell arithmetic and is intended for small nonnegative inputs.
Tested on Ubuntu 24.04.5 LTS · · GNU bash, version 5.2.21(1)-release (x86_64-pc-linux-gnu) · bash 5.2.21-2ubuntu4; coreutils 9.4-3ubuntu6.3
Test inputs, results and environment
The exact published code ran in a dedicated Linux test container with prepared inputs. Snippet process uid 65534 with a read-only root filesystem and temporary working files. Networking disabled. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.
- Architecture / host kernel
- x86_64 / 6.18.54.1-microsoft-standard-WSL2
- Snippet identity / locale
- uid=65534, gid=65534 (unprivileged process) / C.UTF-8
- Interpreter invocation
bash -euo pipefail -c <published code>- Container image ID
sha256:ec91410a8f6ec3e985830b5e3a0560306d36f8c1c5ccd91a6699abe707123fa3- Code SHA-256
79fec163a65eae9a313c81790b97a1c552566e68d9b05a8f012281e752127207- Dependencies
- bash 5.2.21-2ubuntu4; coreutils 9.4-3ubuntu6.3
Test input setup
These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.
# No input files required.
Observed standard output
120
Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.