https://rednafi.com/tags/shell/ Recent content in Shell on Redowan's Reflections https://blob.rednafi.com/static/images/home/cover.png https://rednafi.com/ Hugo -- 0.160.1 en Sat, 28 Mar 2026 14:28:41 +0100 https://rednafi.com/shards/2026/03/background-jobs-inherited-fd/ Sat, 28 Mar 2026 00:00:00 +0000 https://rednafi.com/shards/2026/03/background-jobs-inherited-fd/ Why & backgrounds execution but doesn't stop output from flooding your terminal. Shell Unix https://rednafi.com/misc/dynamic-shell-variables/ Sat, 11 Jan 2025 00:00:00 +0000 https://rednafi.com/misc/dynamic-shell-variables/ Learn variable indirection in Bash with ${!var} syntax. Build context-aware configs, function dispatch, and dynamic variable name resolution. Shell Unix TIL CLI https://rednafi.com/misc/run-single-instance/ Tue, 31 Dec 2024 00:00:00 +0000 https://rednafi.com/misc/run-single-instance/ Prevent multiple script instances with file locking. Use flock in Bash, fcntl in Python, and syscall.Flock in Go for single-instance processes. Shell Unix Python Go https://rednafi.com/misc/ssh-saga/ Tue, 17 Dec 2024 00:00:00 +0000 https://rednafi.com/misc/ssh-saga/ Complete SSH setup guide: key pairs, authorized_keys, sshd_config, ssh_config, known_hosts, agent forwarding, and hardening for secure remote access. Shell Unix Networking Security https://rednafi.com/misc/direnv/ Wed, 02 Oct 2024 00:00:00 +0000 https://rednafi.com/misc/direnv/ Automate environment variables per directory with direnv. Load .envrc files on entry, unload on exit. Integrate with Python venv and uv workflow. TIL Shell Unix CLI https://rednafi.com/misc/bash-namerefs/ Fri, 20 Sep 2024 00:00:00 +0000 https://rednafi.com/misc/bash-namerefs/ Master Bash namerefs with declare -n to create dynamic variable references. Build generic functions for arrays and associative arrays without eval. Shell Unix TIL CLI https://rednafi.com/misc/shell-redirection/ Thu, 12 Sep 2024 00:00:00 +0000 https://rednafi.com/misc/shell-redirection/ Complete guide to Bash redirection. Master stdout, stderr, pipes, tee, file descriptors, and shorthand syntax with practical examples for every case. Shell Unix https://rednafi.com/misc/http-requests-via-dev-tcp/ Thu, 08 Aug 2024 00:00:00 +0000 https://rednafi.com/misc/http-requests-via-dev-tcp/ Make raw HTTP requests with Bash's /dev/tcp file descriptor. Build health check scripts without curl or wget using TCP socket connections. TIL Shell Unix Networking https://rednafi.com/misc/install/ Sun, 28 Jul 2024 00:00:00 +0000 https://rednafi.com/misc/install/ Replace mkdir, cp, and chmod with a single install command. Copy files, create directories, and set permissions in one step with GNU coreutils. Shell Unix TIL CLI https://rednafi.com/misc/heredoc-headache/ Fri, 19 Jul 2024 00:00:00 +0000 https://rednafi.com/misc/heredoc-headache/ Avoid here-doc pitfalls when running remote commands via SSH. Learn variable expansion gotchas and simpler alternatives for deployment scripts. Shell Unix DevOps GitHub https://rednafi.com/misc/on-rebasing/ Tue, 18 Jun 2024 00:00:00 +0000 https://rednafi.com/misc/on-rebasing/ Master git rebase for cleaner commit history. Learn interactive rebasing, squashing commits, and rebasing feature branches onto main with practical examples. git Shell Unix GitHub https://rednafi.com/misc/pesky-little-scripts/ Sun, 29 Oct 2023 00:00:00 +0000 https://rednafi.com/misc/pesky-little-scripts/ Organize custom scripts with comma-prefixed naming. Improve tab completion and eliminate clutter by prefixing script names with special characters. Shell Unix CLI https://rednafi.com/misc/dotfile-stewardship-for-the-indolent/ Wed, 27 Sep 2023 00:00:00 +0000 https://rednafi.com/misc/dotfile-stewardship-for-the-indolent/ Manage dotfiles across devices with GNU Stow. Symlink configuration files from git repo to home directory with simple, idempotent commands. Shell Unix TIL CLI https://rednafi.com/misc/dns-record-to-share-text/ Mon, 17 Jul 2023 00:00:00 +0000 https://rednafi.com/misc/dns-record-to-share-text/ Share data via DNS TXT records using dig and base64 encoding. Learn limitations, security concerns, and practical use cases for DNS tunneling. Shell Unix TIL Networking https://rednafi.com/python/unix-style-pipeline-with-subprocess/ Fri, 14 Jul 2023 00:00:00 +0000 https://rednafi.com/python/unix-style-pipeline-with-subprocess/ Build Unix-style command pipelines in Python using subprocess.run with stdout piping for efficient process chaining and output capture. Python TIL Shell Unix https://rednafi.com/python/implement-traceroute/ Thu, 01 Jun 2023 00:00:00 +0000 https://rednafi.com/python/implement-traceroute/ Build a traceroute clone in Python using UDP and ICMP sockets to trace network packet routes and measure hop latency with TTL manipulation. Python Networking Shell Unix https://rednafi.com/misc/fixed-time-task-scheduling-with-at/ Sun, 14 May 2023 00:00:00 +0000 https://rednafi.com/misc/fixed-time-task-scheduling-with-at/ Schedule one-time commands with UNIX at command. Learn job queuing, remote scheduling via HTTP API, and managing atd/atrun daemons. Shell Unix JavaScript Networking https://rednafi.com/misc/associative-arrays-in-bash/ Wed, 03 May 2023 00:00:00 +0000 https://rednafi.com/misc/associative-arrays-in-bash/ Learn how to use associative arrays in Bash to create key-value pairs, mimic dictionaries, and manage complex data structures in shell scripts. Shell Unix TIL Data Structures https://rednafi.com/misc/process-substitution-in-bash/ Sun, 30 Apr 2023 00:00:00 +0000 https://rednafi.com/misc/process-substitution-in-bash/ Use process substitution <() to treat command output as files in Bash. Compare directories, process data, and avoid temporary files with this technique. Shell Unix TIL https://rednafi.com/misc/dynamic-menu-with-select-in-bash/ Sat, 29 Apr 2023 00:00:00 +0000 https://rednafi.com/misc/dynamic-menu-with-select-in-bash/ Build interactive CLI menus with Bash select statement. Create user-friendly command-line tools with option selection and function dispatch. Shell Unix TIL CLI https://rednafi.com/misc/terminal-text-formatting-with-tput/ Sun, 23 Apr 2023 00:00:00 +0000 https://rednafi.com/misc/terminal-text-formatting-with-tput/ Format terminal output with tput instead of ANSI codes. Set colors, bold text, underlines, and backgrounds with simple commands in shell scripts. Shell Unix TIL CLI https://rednafi.com/misc/tinkering-with-unix-domain-socket/ Sat, 11 Mar 2023 00:00:00 +0000 https://rednafi.com/misc/tinkering-with-unix-domain-socket/ Build Unix domain socket servers and clients with Python and socat. Access Docker API via UDS, create HTTP servers, and optimize inter-process communication. Python Shell Unix Networking https://rednafi.com/misc/colon-command-in-shell-scripts/ Fri, 23 Dec 2022 00:00:00 +0000 https://rednafi.com/misc/colon-command-in-shell-scripts/ Use the colon : command as a no-op in Bash scripts for cleaner debug output with -x flag. Alternative to echo for section markers and comments. Shell Unix TIL CLI https://rednafi.com/misc/audit-commit-messages-on-github/ Thu, 06 Oct 2022 00:00:00 +0000 https://rednafi.com/misc/audit-commit-messages-on-github/ Automate commit message validation with GitHub Actions. Enforce refs and closes patterns to maintain clean Git history and link commits to issues. GitHub DevOps Shell Unix https://rednafi.com/misc/to-quote-or-not-to-quote/ Wed, 05 Oct 2022 00:00:00 +0000 https://rednafi.com/misc/to-quote-or-not-to-quote/ Master shell quoting rules: single vs double quotes, backticks vs $(). Learn when to quote variables to prevent spaces and special characters from breaking commands. Shell Unix https://rednafi.com/misc/return-values-from-a-shell-function/ Sun, 25 Sep 2022 00:00:00 +0000 https://rednafi.com/misc/return-values-from-a-shell-function/ Understand how return values work in Bash functions. Learn exit codes, status evaluation patterns, and proper boolean returns with true/false commands. Shell Unix TIL https://rednafi.com/misc/distil-git-logs-attached-to-a-file/ Tue, 21 Jun 2022 00:00:00 +0000 https://rednafi.com/misc/distil-git-logs-attached-to-a-file/ View git commit history for a single file with git log --follow. Learn to track multiple files with xargs and concatenate their commit logs. Shell Unix Git TIL https://rednafi.com/misc/health-check-a-server-with-nohup/ Mon, 18 Apr 2022 00:00:00 +0000 https://rednafi.com/misc/health-check-a-server-with-nohup/ Run background health checks in CI with nohup and ampersand. Test server readiness with retry loops and automatic cleanup on success or failure. Shell Unix TIL DevOps https://rednafi.com/misc/do-not-add-extensions-to-bash-executables/ Tue, 23 Nov 2021 00:00:00 +0000 https://rednafi.com/misc/do-not-add-extensions-to-bash-executables/ Why executable scripts shouldn't have extensions. Learn GitHub's scripts-to-rule-them-all pattern for language-agnostic project automation. Shell Unix TIL CLI https://rednafi.com/misc/use-command-v-over-which/ Tue, 16 Nov 2021 00:00:00 +0000 https://rednafi.com/misc/use-command-v-over-which/ Replace which with command -v for POSIX-compliant executable lookup. Learn why command -v is the portable alternative for finding program paths. Shell Unix TIL CLI