Linux Error Reference
1 model · 38 error codes
Browse Linux error code collections, meanings, and related context across the current corpus.
About Linux Error Reference
Linux error reporting operates through two distinct mechanisms: process exit codes (0–255) and kernel signals. Exit codes communicate the outcome of a process to its parent, while signals (such as SIGSEGV, SIGKILL, SIGTERM) are asynchronous notifications sent by the kernel when exceptional conditions occur — memory violations, illegal instructions, or external termination requests.
The C library also defines a set of errno constants (ENOMEM, EIO, EACCES, and dozens more) that functions use to report specific failure types. These errno values are the lowest-level error reporting mechanism in Linux and form the basis for higher-level error messages seen in applications, package managers, and system services.
FixerCode documents 38 Linux error codes and signals across 1 model, covering both signal-based termination codes (such as exit code 137 from SIGKILL) and errno-based failure constants. Each entry explains the signal or errno meaning, common triggers, and related kernel behaviors.
Select Your Model 1
Frequently Asked Questions
An exit code (0–255) is the value a process returns to its parent when it finishes. A signal is an asynchronous notification sent by the kernel to a process while it is running. When a process is killed by a signal, its exit code is typically 128 plus the signal number.
Exit code 137 usually means the process was killed by SIGKILL (signal 9). This happens when the system runs out of memory (OOM killer) or when a process is manually terminated with kill -9.
errno values are integer constants defined in the C standard library (errno.h) that describe specific failure types. Common examples include ENOMEM (out of memory), EIO (input/output error), and EACCES (permission denied). Functions set errno when they fail, and applications read it to determine the cause.