Navigation (cd, pwd)

# 1) Basics
pwd                                   # /home/mara/projects/app
cd /etc/nginx                          # absolute path
cd nginx.conf                           # NOPE — cd needs a directory; this errors
cd ~                                    # home
cd ~mara                                 # mara's home
cd                                       # also home
cd ..                                    # parent
cd ../sibling                            # parent's sibling
cd -                                     # PREVIOUS directory (toggle)

# 2) Show what's there
ls                                       # current dir
ls -la                                    # long + hidden (dotfiles)
ls -lh                                    # human-readable sizes
ls -lt                                    # newest first
ls -1                                     # one entry per line (scripts)
tree -L 2                                 # 2-level tree (install: brew/apt install tree)

# 3) Globbing — shell expands paths before commands see them
ls *.md                                  # all top-level .md files
ls **/*.test.ts                           # globstar — requires shopt -s globstar (bash)
ls assets/*.{png,jpg,webp}                # brace expansion (alternatives)
ls ./.{git,vscode,idea}/                  # hidden dirs by name

# 4) Show + go in one move
ls ~/projects/app/src                   # see what's there
cd !$                                   # !$ = last word of previous command — re-uses path
# Result: cd ~/projects/app/src

# 5) Directory stack — pushd / popd / dirs
pushd ~/projects/app                    # cd there + push old onto stack
pushd /etc/nginx                         # cd there + push again
dirs -v                                   # see the stack
# 0  /etc/nginx
# 1  ~/projects/app
# 2  ~/projects/old-dir
popd                                      # pop top, cd back
cd ~+2                                    # cd to stack item index 2 (bash)

# 6) History shortcuts
!!                                        # repeat last command
sudo !!                                   # repeat with sudo prefix
!?nginx                                    # last command containing 'nginx'
!42                                       # history command number 42
^old^new                                  # rerun last command replacing 'old' with 'new'
!$                                       # last argument of previous command
!^                                        # FIRST argument of previous command
!*                                        # all args of previous command

# 7) Reverse search
Ctrl+R       cd /etc                       # incrementally search history (very useful)
Ctrl+R       Ctrl+R                         # cycle through matches
# Modern alternatives: atuin (great history), mcfly (ML-ranked), or fzf integration:
#   ~/.bashrc:  bind -x '"\C-r": __fzf_history__'    (after sourcing fzf shell completions)

# 8) Modern replacements
z projects/app                             # 'zoxide' (or 'z') — jumps based on history of cd-d places
z nginx                                     # cd ~/work/something/nginx (fuzzy match)
fd 'name' src/                              # find replacement; respects .gitignore
eza -la --git                                # modern ls with git status
bat path/file                                # cat with syntax highlight + paging
fzf                                         # fuzzy-find files; integrate with cd: alias cdf='cd $(fd -t d | fzf)'

# 9) Useful aliases (~/.bashrc or ~/.zshrc)
alias ll='ls -la'
alias la='ls -A'
alias ..='cd ..'
alias ...='cd ../..'
alias ....='cd ../../..'
alias home='cd ~'
alias work='cd ~/work'
alias src='cd $(git rev-parse --show-toplevel)/src'

# 10) Symbolic links — readlink + cd -P
cd /usr/local/bin/python                   # follows symlink
pwd                                         # logical path (symlink path)
pwd -P                                      # PHYSICAL path (resolved)
readlink -f /usr/local/bin/python            # canonical resolved path

# Disable symlink-following globally:
set -P                                        # pwd shows physical paths

# 11) Bash CDPATH — auto-search common dirs
export CDPATH=".:$HOME:$HOME/projects:/srv"
cd app                                       # finds ~/projects/app even though you're not there
# Use sparingly — confuses scripts.

# 12) Going home and exploring quickly
take projects/new-thing                      # mkdir -p + cd into it (zsh function; copy to bash)
mkcd() { mkdir -p "$1" && cd "$1"; }

# 13) Useful prompts (PS1)
export PS1='\\[\\e[34m\\]\\w\\[\\e[0m\\] $ '   # show full path
# Or use starship / oh-my-posh for richer prompts with git status.

# 14) Going to a sibling project — find + cd
cd "$(find ~/work -type d -name '*api*' -maxdepth 3 | fzf)"

# 15) Common bugs
# • cd into a file by accident → 'not a directory'; use ls then cd
# • cd - keeps toggling between two dirs forever; use pushd/popd for a stack
# • Hidden assumption: scripts run with PWD = where they're invoked from, not where the script lives
#   Use 'cd "$(dirname "${BASH_SOURCE[0]}")"' at the top of scripts to anchor
# • CDPATH side effects on scripts — leave it off in non-interactive shells
# • Aliases not loading in scripts — alias only works in interactive shells; use functions
# • Spaces in paths — quote: cd "$HOME/My Documents"
# • Symlinks confusing relative paths — pwd -P for physical, pwd for logical

pwd                    # print current directory
cd /var/log
cd ~ && cd -            # home and previous