Debugging
5 pagescoredumpctl: Finding a Binary Crash
What is coredumpctl and how it works When a binary crashes with SEGV, the kernel can save a core dump — a snapshot of process memory at the moment of the crash. In systemd-based distributions, coredumpctl handles collecting, storing, and searching …
What is coredumpctl and how it works When a binary crashes with SEGV, the kernel can save a core dump — a snapshot of process memory at the moment of the crash. In systemd-based distributions, coredumpctl handles collecting, storing, and searching …
lsof: which processes listen on port and hold file
Service won’t start — port 8080 is already bound. You dig into who’s holding it, and discover the same process has your config file open while you’re trying to edit it. lsof answers both questions: which processes opened which files and sockets. …
Service won’t start — port 8080 is already bound. You dig into who’s holding it, and discover the same process has your config file open while you’re trying to edit it. lsof answers both questions: which processes opened which files and sockets. …
curl: HTTP Debugging in CLI
cURL is the standard tool for debugging HTTP in the terminal. It ships out of the box on Linux and macOS and is present in most Docker images. Need to quickly check an API, inspect response headers, or trace a redirect issue — one command line is …
cURL is the standard tool for debugging HTTP in the terminal. It ships out of the box on Linux and macOS and is present in most Docker images. Need to quickly check an API, inspect response headers, or trace a redirect issue — one command line is …
strace: System Call Tracing for Diagnosing Hangs and Leaks
When a service hangs, standard tools like top, htop, and ps show the state but not the cause. If a process is in state D (uninterruptible sleep), it’s waiting on a syscall. strace attaches to a live process and outputs every system call in real time. …
When a service hangs, standard tools like top, htop, and ps show the state but not the cause. If a process is in state D (uninterruptible sleep), it’s waiting on a syscall. strace attaches to a live process and outputs every system call in real time. …
ngrep: grep for Network Packets in Real Time
Ngrep applies grep-style pattern matching to network packets. When you need to see exactly what two services are exchanging over the wire and tcpdump drowns you in noise, ngrep isolates the payload content you care about. Installation Ngrep ships in …
Ngrep applies grep-style pattern matching to network packets. When you need to see exactly what two services are exchanging over the wire and tcpdump drowns you in noise, ngrep isolates the payload content you care about. Installation Ngrep ships in …