Command-line tool

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Useful built-in (macOS) command-line tools with examples.

curl

Client for URLs. Basic usage is for transfering data to and from servers using URLs.

Example

Request the contents of example.com.

Terminal window
$ curl example.com


<!doctype html><html lang="en"><head><title>Example Domain</title><link rel="icon" href="data:,"><meta name="viewport" content="width=device-width, initial-scale=1"><style>body{background:#eee;width:60vw;margin:15vh auto;font-family:system-ui,sans-serif}h1{font-size:1.5em}div{opacity:0.8}a:link,a:visited{color:#348}</style></head><body><div><h1>Example Domain</h1><p>This domain is for use in documentation examples without needing permission. Avoid use in operations.</p><p><a href="https://iana.org/domains/example">Learn more</a></p></div></body></html>

dig

Domain information groper. Basic usage is for querying DNS records for a domain.

Example

Query A records for the domain example.com.

Terminal window
$ dig example.com A


;; ANSWER SECTION:
example.com.            133     IN      A       104.20.23.154
example.com.            133     IN      A       172.66.147.243

grep

Global regular expression print. Basic usage is for searching for text in a file using a regular expression, and print any lines that contain a match.

Example

Search, ignoring case (-i), for any line that start with “hello” in the file greeting.txt.

Terminal window
$ grep -i "^hello" greeting.txt
Hello, world!

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