Replace text with sed.
Replace all occurrences of the substring old on each line and print the transformed text without changing the input file.
sed 's/old/new/g' notes.txtExpected output EXAMPLE
new name, new path
Details
Run in Bash on GNU/Linux. Uses the standard tools supplied with Ubuntu; no elevated permissions are required.
sed uses regular expressions. This example leaves the original file intact; redirect to a different filename to save the result.
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; sed 4.9-2ubuntu0.24.04.1
Test inputs, results and environment
The exact published code ran in a dedicated Linux test container with prepared inputs. Unprivileged snippet process, external networking disabled, read-only root filesystem, and a fresh temporary working directory. 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) / C.UTF-8
- Interpreter invocation
bash -euo pipefail -c <published code>- Container image ID
sha256:32dc2d998158b6554c99b73b533f423696a0f3e31e8cbea9db10b5eee9a2fadd- Code SHA-256
7c261313bbc6c2a1f06edf9f1ae26faeadff4bfb228086bc333d0d1ba76e0a08- Dependencies
- bash 5.2.21-2ubuntu4; sed 4.9-2ubuntu0.24.04.1
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 'old name, old path\n' > notes.txt
Observed standard output
new name, new path
Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.
Additional assertions that passed
Checks recorded by the test harness. Where Python assertions are shown, browser cases use Playwright and simulator cases may inspect pin transitions: result.stdout is captured output, work is the temporary directory, and Path is pathlib.Path. The harness also imports json and csv.
assert Path('notes.txt').read_text() == 'old name, old path\n'