Check that a file is present and nonempty.

Test file content availability before reading it.

set -euo pipefail
if [[ -s settings.txt ]]; then
  printf "Settings ready\n"
else
  printf "Settings missing or empty\n"
fi

Expected output EXAMPLE

Settings ready

Details

Requires Bash 4 or later. Save as snippet.sh and run bash snippet.sh in an empty working directory. The -s test checks that the file exists and has a size greater than zero.

✓ Verified

Tested on Ubuntu 24.04.5 LTS · 2026-11-02 18:21:08 UTC · 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: 17f5a46c6c6eedfcef898a63d2d8e461037eb1ba36a0006f7d11abae37dc73cf
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.

printf 'mode=dev\n' > settings.txt

Observed standard output

Settings ready

Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.