A script fails, you check echo $?, and you get back a number like 137 or 143 with no further explanation — Bash doesn’t tell you what it means, and the meaning changes depending on whether the number came from a normal error or from a signal. This tool turns that bare number into a plain-English answer instantly.
What Is the Linux Exit Code Lookup?
Type any exit code into the input and get an immediate explanation, including recognizing the 128 + signal number pattern used for any process killed by a signal — even ones not in the static reference table. Below it, a searchable table covers the most common codes you’ll actually encounter: 0-2, 126-127, and the signal-based codes from 128 through 255.
How to Use It
- Open the tool at /tools/linux-exit-code-lookup.
- Type the exit code you got from
echo $?or your CI logs into the lookup box. - Read the plain-English meaning and common cause.
- Or search the full reference table by code or keyword (like “kill” or “segfault”).
Key Features
- Instant, plain-English explanation for any code 0-255, not just the ones in the static table.
- 128+signal detection — enter 150 and it tells you that’s signal 22, even without a dedicated table row.
- Searchable reference table covering the most frequently seen codes, including 137 (SIGKILL/OOM), 139 (segfault), and 143 (SIGTERM).
- Zero setup — no need to grep man pages or search Stack Overflow mid-incident.
When to Use This Tool
- Debugging a Docker container that keeps exiting with 137 (almost always an out-of-memory kill).
- Investigating a CI pipeline failure where the runner reports an unfamiliar exit code.
- Learning what Bash exit code conventions actually mean while writing your own scripts.
Try It Now
Open Linux Exit Code Lookup directly, or press ⌘K and type the tool name from anywhere on the site.
Part of the DevOps Tools collection on WebdevToolbox — free, browser-based developer tools with no login required.