Shell Mastery — Cross-Platform CLI Fluency

Cross-platform CLI fluency across bash, zsh, PowerShell, and perl. Organized by skill domain, not tool. Competition-ready, airgapped-capable.

Disciplines

Discipline	Description
Builtins	Shell builtins, compgen discovery
bash vs zsh	Key differences: arrays, globs, splitting, prompts, associative arrays, process sub, extended glob
Perl	Perl one-liners, perl vs awk vs sed comparison table
Exit Codes	$?, $LASTEXITCODE, common codes, conditionals
Data Manipulation	PATH manipulation, CSV transforms, env inspection, text transforms
Process Forensics	Process inspection, file forensics, SUID, world-writable, network connections
Power Moves	One-liner power moves, parallel xargs, passwords, hex, base64, checksums
PowerShell jq/yq	jq and yq on PowerShell, ConvertTo-Json pipeline
Metasyntactic	foo/bar/baz origin, canonical sequence, professional alternatives
Airgapped Survival	System discovery, grep/find/awk/sed on unknown systems, pipes combos, reading system docs
Server Survival	Quick survival commands, what shell am I, POSIX fallback, history tricks, compgen for tools
Alternate Commands	Multiple ways to do the same task — file creation (10 ways), [[ ]] vs [ ], conditionals, permissions
File Descriptors	stdin/stdout/stderr, custom fds 3-9, redirection, named pipes, /proc/fd, man page search patterns

Discipline

Description

Shell builtins, compgen discovery

Key differences: arrays, globs, splitting, prompts, associative arrays, process sub, extended glob

Perl one-liners, perl vs awk vs sed comparison table

$?, $LASTEXITCODE, common codes, conditionals

PATH manipulation, CSV transforms, env inspection, text transforms