unix
7 minUnix Signals and Child Processes: What Your Service Must Clean Up
Follow signals from a container stop through shell wrappers and child processes, and build shutdown behavior that preserves work.
Search the library
29 matching resultsArticles and interview answers
distributed systems
6 minFencing tokens: reject workers whose lease has expired
Protect a shared resource from stale owners instead of assuming expired leases stop processes.
Q&A
Q&AWhy can a Linux filesystem be full when du shows free space?
Inodes may be exhausted, or deleted files may still be held open by running processes.
Read the concise answer
Compare df -h with df -i. If block usage and directory totals disagree, inspect open-but-deleted files with lsof +L1. A process retains allocated blocks until it closes the file; restart or signal the owning service through its safe lifecycle after confirming the file is disposable.
Q&A
Q&AWhat can a subprocess inherit across exec?
Environment strings and open descriptors not marked close-on-exec.
Read the concise answer
Construct a deliberate environment and descriptor allowlist. Descriptors grant capabilities to files, sockets, or pipes; inherited writers can delay EOF and inherited secrets can leak to less-trusted children.
unix
8 minpipefail, Signals, and Unix Process Management
Unix is full of tiny control primitives. Learn how `set -o pipefail`, process signals, and clean lifecycle management keep shell pipelines reliable and debuggable.
devops
6 minScheduled jobs: separate a logical run from its attempts
Give retries a stable business identity without confusing schedule windows with process start times.
unix
8 minUnix process inheritance: environment variables and file descriptors
Trace what survives fork and exec, and close capabilities a child should not inherit.
Q&A
Q&AWhen should you use grep, sed, or awk?
Use grep to select lines, sed for stream edits, and awk for field-based filtering and calculations.
Read the concise answer
grep selects matching lines; sed applies stream transformations such as substitutions; awk processes records and fields. Quote patterns for the shell, test edits on copied input, and do not treat default awk splitting as a full CSV parser. For structured formats or complex quoting, use a format-aware parser.