unix-cli-best-practices

Unix CLI best practices

This guide provides efficient, safe, and portable techniques for manipulating text and finding files from the command line on macOS. By default, macOS uses BSD-derived UNIX utilities (grep, find, sed, awk) which have subtle differences from their GNU/Linux counterparts.

When possible, use high-performance replacements (ripgrep and fd) which respect .gitignore rules by default and offer more ergonomic interfaces.

Modern high-performance alternatives

Use these tools instead of standard BSD utilities for local codebase operations.

ripgrep (rg)

Use ripgrep (rg) as the preferred tool for searching text. It is faster than standard grep and respects .gitignore rules by default.

Common use cases:

• Run rg 'search_term' to recursively search the current directory.
• Run rg -S 'term' to search case-insensitively unless the query contains uppercase letters. Use rg -i 'term' for strict case-insensitivity.
• Run rg -g '*.ts' -g '!*.spec.ts' 'term' to search .ts files while excluding .spec.ts files.
• Run rg -v 'ignore_me' to print lines that do not match the pattern.
• Run rg -l 'term' to list only the names of matching files. Combine with rg -0 for null-terminated output suitable for xargs.
• Run rg -F 'foo()' to treat the search pattern as a fixed string rather than a regular expression.
• Run rg -w 'const' to match whole words only.
• Run rg -C 2 'term' to show two lines of surrounding context. Use rg -B 2 for preceding context or rg -A 2 for succeeding context.

Refer to rg --help for the complete options list.

fd

Use fd as the preferred tool for traversing the filesystem and finding files. It is faster than standard find and respects .gitignore rules by default.

Common use cases:

• Run fd 'pattern' to find files matching the regex pattern anywhere in their path.
• Run fd -e py -e txt to filter results by file extensions.
• Run fd -t d 'docs' to find directories. Use fd -t f for files and fd -t l for symbolic links.
• Run fd -H to include hidden files, or fd -I to include ignored files (such as node_modules). Combine as fd -HI to search all files.
• Run fd -p 'src/assets' to match the pattern against the full path instead of just the filename.
• Run fd -e log -x rm to execute a command on each matching file individually. Use -X (e.g., fd -e log -X rm) to run the command once with all matching files as arguments.
• Run fd -a 'pattern' to return absolute paths instead of relative paths.