What should you write before choosing a command?	Write the question you are trying to answer: path, file, service, logs, disk, domain, or permissions.	topicladder command-line reference
Why start with `pwd`?	`pwd` proves the current directory before path-sensitive commands run from the wrong place.	topicladder command-line reference
What does `ls -lah` help inspect?	Names, hidden entries, permissions, owners, sizes, and timestamps in the current directory.	topicladder command-line reference
When is `find . -maxdepth 2 -type f` useful?	When you need a bounded local file inventory without crawling the whole machine.	topicladder command-line reference
Why use `head -40 file.txt` before `cat`?	It previews a bounded part of a file and avoids dumping huge logs or configs.	topicladder command-line reference
What does `grep -n` add?	Line numbers, so a match can be discussed, cited, or saved in a project note.	topicladder command-line reference
What does `namei -l /path/to/file` prove?	It walks every path component and can reveal a parent directory permission problem.	topicladder command-line reference
What does `stat -c '%A %U:%G %n'` show?	Mode, owner, group, and name in one compact line.	topicladder command-line reference
Why check `id` during permission triage?	It shows the current user and groups actually available to the shell.	topicladder command-line reference
What does `git status --short` show?	A compact list of modified, added, deleted, or untracked files.	topicladder command-line reference
Why inspect `git diff -- path/to/file`?	It explains one file's unstaged changes before committing or reverting.	topicladder command-line reference
What does `ss -ltnp` prove?	Which TCP ports are listening and which process owns them.	topicladder command-line reference
Why use `curl -I`?	It checks headers, status, redirects, and TLS behavior without downloading the full page.	topicladder command-line reference
What does `systemctl status nginx --no-pager` show?	Service state, recent failure text, and unit metadata without opening a pager.	topicladder command-line reference
Why scope `journalctl` with `-u` and `--since`?	It keeps log reading focused on one service and a useful time window.	topicladder command-line reference
What is the difference between `df -h` and `df -i`?	`df -h` checks bytes; `df -i` checks inode availability.	topicladder command-line reference
Why use `du -xhd1 /var 2>/dev/null | sort -h`?	It ranks top-level directory sizes without crossing filesystems.	topicladder command-line reference
What does `dig +short example.com A` answer?	Which IPv4 addresses DNS currently returns for the domain.	topicladder command-line reference
Why test HTTP before TLS?	It separates DNS and web-server reachability from certificate problems.	topicladder command-line reference
What should you record after a command?	The command, expected signal, actual result, and next action.	topicladder command-line reference