Bash Scripting for Developers

What is Bash and why developers use it

shell vs terminal, Bash vs sh vs zsh, Unix philosophy, shebang line, script execution model, PATH variable

Bash variables and quoting rules explained

variable assignment, dollar-sign expansion, single vs double quotes, unset variables, readonly, local scope, word splitting

How Bash exit codes and error handling work

exit codes, $? variable, set -e, set -u, set -o pipefail, trap ERR, command success vs failure convention

Bash input and output redirection fundamentals

stdin stdout stderr, file descriptors 0 1 2, redirect operators, /dev/null, tee command, heredoc, pipe operator

Command substitution and arithmetic in Bash

command substitution $(), backtick syntax, arithmetic expansion $(( )), let builtin, bc for floats, expr limitations, integer vs float handling

Bash if statements and test conditions

if elif else syntax, test command, [ ] vs [[ ]], string comparison, numeric comparison operators, file test operators, compound conditions

Bash for loops and while loops with examples

C-style for loop, for-in loop, while loop, until loop, break and continue, loop over files, loop over command output, IFS variable

Bash case statement for multi-branch logic

case syntax, pattern matching, wildcard patterns, | alternation in case, ;; vs ;& vs ;;& terminators, case vs if-elif chain, argument parsing with case

Bash arrays and how to iterate them correctly

indexed arrays, array declaration, array access, array length, array slicing, associative arrays, iterate with for, append to array, unset array element

Bash select menu and user input handling

select statement, read command, read -p prompt, read -s silent input, read -t timeout, PS3 variable, validating user input, reading from stdin vs arguments

How to write and call Bash functions

function declaration syntax, calling functions, return values, return vs exit, function arguments $1 $2, local variables, function scope, overriding built-ins

Bash local variables and scope explained

global vs local scope, local keyword, dynamic scoping in Bash, function side effects, nameref variables, subshell scope, environment vs shell variables, export

Bash script structure and sourcing files

script organization pattern, sourcing with dot operator, source vs execute, library scripts, guard against re-sourcing, __dirname equivalent, relative paths in scripts

How to write a Bash logging library

log levels, color output with tput, stderr vs stdout logging, log to file and terminal simultaneously, timestamps in logs, log verbosity flag, disabling color in CI

Bash argument parsing with getopts

getopts vs getopt, short option syntax, option with argument, OPTARG OPTIND, error handling in getopts, required vs optional arguments, help flag pattern, shift after getopts

grep, sed, and awk — which tool to use when

grep pattern matching, sed stream editing, awk field processing, when to use each tool, extended regex, in-place editing with sed, awk field separator, combining tools in pipelines

Bash string manipulation without external tools

parameter expansion, substring extraction, string length, find and replace in variables, prefix and suffix stripping, default values, case conversion, string splitting with IFS

Parsing CSV and JSON in Bash scripts

IFS-based CSV parsing, limitations of Bash CSV parsing, jq for JSON, jq filters and select, extracting values from API responses, iterating JSON arrays with jq, jq as a dependency

Bash file and directory operations at scale

find command, find with exec, xargs for bulk operations, mktemp, file locking with flock, recursive operations, handling special filenames, stat command, file permissions with chmod

Bash regex matching and string validation

=~ operator in [[ ]], BASH_REMATCH array, ERE syntax, validating email IP UUID date formats, regex vs glob, anchoring patterns, character classes, negation

Bash background jobs and job control explained

background with &, jobs command, wait builtin, fg and bg, disown, nohup, job IDs vs PIDs, parallel execution pattern, collecting exit codes from background jobs

Bash signals and trap for graceful shutdown

Unix signals, SIGTERM SIGINT SIGKILL SIGHUP, trap syntax, trap with signal names, cleanup on exit, forwarding signals to child processes, kill command, signal numbers

Scheduling Bash scripts with cron and systemd timers

cron syntax, crontab fields, crontab -e, environment in cron, systemd timer units, OnCalendar syntax, cron vs systemd comparison, logging cron jobs, run-parts, anacron

How to monitor and manage Bash script processes

ps and pgrep, kill and pkill, pidfile pattern, wait with timeout, process substitution, /proc filesystem, lsof for open files, monitoring script health with while loop

Bash parallel processing with xargs and GNU parallel

xargs -P for parallelism, GNU parallel basics, parallel vs xargs, controlling job count, parallel with progress, collecting output, handling failures in parallel, rate limiting

Bash script testing and debugging techniques

set -x tracing, bash -n syntax check, shellcheck static analysis, set -v verbose, PS4 variable, bats testing framework, assert functions, testing functions in isolation, debugging subshells

Managing secrets and environment variables in Bash

never hardcode secrets, environment variable injection, .env file loading, printenv and env auditing, secret masking in logs, vault and AWS SSM integration patterns, secure temporary files, variable sanitization

Building a CI/CD deployment script in Bash

deployment script structure, pre-deploy checks, blue-green deployment pattern, rollback mechanism, health check loop, deployment lock, notifications via curl webhook, idempotency

Bash scripts for Docker and Kubernetes automation

docker CLI in scripts, waiting for containers, kubectl in scripts, checking pod status, applying manifests, waiting for rollout, namespace operations, image tagging patterns, docker compose in CI

Building a self-contained Bash CLI tool

CLI tool structure, subcommand dispatch, help generation, version flag, --completion support, color detection, install and uninstall targets, Makefile integration, distributing Bash scripts