Remove blank or whitespace-only lines.
Linux Commands: Use a POSIX character class so tabs and spaces are handled together.
sed '/^[[:space:]]*$/d' lines.txtExpected output EXAMPLE
one two
Details
Run in Bash on GNU/Linux in a scratch directory. Tested with the GNU utilities supplied by Ubuntu. Use a POSIX character class so tabs and spaces are handled together.
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; 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
1c8f41b4ff1a13bb82b9f409b4c42f2d7e8b1d4df7ee343b97e9cb8b294cc445- Dependencies
- bash 5.2.21-2ubuntu4; coreutils 9.4-3ubuntu6.3; 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 'one\n \n\t\n\ntwo\n' > lines.txt
Observed standard output
one two
Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.