Explore Codebase

Tool Selection

Need

Tool

Structural patterns (functions, classes)

sg

(ast-grep)

Text/regex patterns (strings, names)

rg

(ripgrep)

File discovery by name/extension

fd

Decision flow

Find files first? fd → pipe to rg / sg . Syntax-aware match needed? sg . Fast text search? rg . Uncertain? Start with rg , escalate to sg if structure matters. ast-grep Essentials ast-grep is the least familiar tool -- key syntax summarized here. See references/ast-grep.md for language-specific patterns and YAML rule files. sg -p 'PATTERN' -l LANG [ PATH ] sg -p 'PATTERN' --has 'INNER' -l LANG

Must contain

sg -p 'PATTERN' --not-has 'INNER' -l LANG

Must not contain

sg -p 'PATTERN' --inside 'OUTER' -l LANG

Must be within

Metavariables Syntax Captures Example $VAR Single node console.log($MSG) $$$VAR Zero or more nodes function($$$ARGS) -- any arity $ Non-capturing $_FUNC($) -- match without capture Rules: must be UPPERCASE, same name = same content ( $A == $A matches x == x not x == y ). Examples sg -p 'function $NAME($$$ARGS) { $$$ }' -l js sg -p 'async function $NAME($$$) { $$$ }' --has 'await $EXPR' -l js sg -p 'class $NAME extends $PARENT { $$$ }' -l ts sg -p 'def $NAME($$$): $$$' -l py ripgrep / fd Quick Reference Standard CLI tools -- use references/ripgrep.md and references/fd.md for full flag tables. rg PATTERN -t TYPE [ PATH ]

Search by file type

rg -F 'LITERAL' -t TYPE

Fixed string (no regex)

rg PATTERN -l

List matching files only

rg PATTERN -C 3

With context lines

fd -e EXT [ PATH ]

Find by extension

fd PATTERN [ PATH ]

Find by name regex

fd -e py | xargs rg 'pattern'

Pipe fd into rg

Performance Narrow scope first: fd -e py src/ | xargs rg 'class.*Test' Always use type filters: rg PATTERN -t rust , sg -p 'PATTERN' -l rs Exclude artifacts: rg PATTERN -g '!node_modules' -g '!dist'