提取 stdin 提供的 URL 的各个部分
如果你已经安装并配置好 Go：
▶ go install github.com/tomnomnom/unfurl@latest
否则，下载适用于你平台的最新二进制文件，解压后将其移动到 $PATH 中的某个位置（例如 /usr/bin/）：
▶ wget https://github.com/tomnomnom/unfurl/releases/download/v0.0.1/unfurl-linux-amd64-0.0.1.tgz
▶ tar xzf unfurl-linux-amd64-0.0.1.tgz
▶ sudo mv unfurl /usr/bin/
unfurl 处理通过 stdin 提供的 URL；这些 URL 可能来自类似这样的文件：
▶ cat urls.txt
https://sub.example.com/users?id=123&name=Sam
https://sub.example.com/orgs?org=ExCo#about
http://example.net/about#contact
你可以使用 domains 模式从 URL 中提取域名：
▶ cat urls.txt | unfurl domains
sub.example.com
sub.example.com
example.net
如果你不想输出重复的值，可以使用 -u 或 --unique 标志：
▶ cat urls.txt | unfurl --unique domains
sub.example.com
example.net
-u/--unique 标志适用于所有模式。
你可以使用 apexes 模式提取域名的 apex 部分（即根域名，例如 http://sub.example.com 中的 example.com）：
▶ cat urls.txt | unfurl -u apexes
example.com
example.net
▶ cat urls.txt | unfurl paths
/users
/orgs
/about
▶ cat urls.txt | unfurl keys
id
name
org
▶ cat urls.txt | unfurl values
123
Sam
ExCo
▶ cat urls.txt | unfurl keypairs
id=123
name=Sam
org=ExCo
▶ cat urls.txt | unfurl json
{"scheme":"https","opaque":"","user":"","host":"sub.example.com","path":"/users","raw_path":"","raw_query":"id=123\u0026name=Sam","fragment":"","parameters":[{"key":"id","value":"123"},{"key":"name","value":"Sam"}],"url":"https://sub.example.com/users?id=123\u0026name=Sam","domain":"sub.example.com","subdomain":"sub","root":"example","tld":"com","apex":"example.com","port":"","extension":""}
{"scheme":"https","opaque":"","user":"","host":"sub.example.com","path":"/orgs","raw_path":"","raw_query":"org=ExCo","fragment":"about","parameters":[{"key":"org","value":"ExCo"}],"url":"https://sub.example.com/orgs?org=ExCo#about","domain":"sub.example.com","subdomain":"sub","root":"example","tld":"com","apex":"example.com","port":"","extension":""}
{"scheme":"http","opaque":"","user":"","host":"example.net","path":"/about","raw_path":"","raw_query":"","fragment":"contact","parameters":null,"url":"http://example.net/about#contact","domain":"example.net","subdomain":"","root":"example","tld":"net","apex":"example.net","port":"","extension":""}
你可以使用 format 模式指定自定义输出格式：
▶ cat urls.txt | unfurl format %d%p
sub.example.com/users
sub.example.com/orgs
example.net/about
可用的格式指令如下：
%% A literal percent character
%s The request scheme (e.g. https)
%u The user info (e.g. user:pass)
%d The domain (e.g. sub.example.com)
%S The subdomain (e.g. sub)
%r The root of domain (e.g. example)
%t The TLD (e.g. com)
%P The port (e.g. 8080)
%p The path (e.g. /users)
%e The path's file extension (e.g. jpg, html)
%q The raw query string (e.g. a=1&b=2)
%f The page fragment (e.g. page-section)
%@ Inserts an @ if user info is specified
%: Inserts a colon if a port is specified
%? Inserts a question mark if a query string exists
%# Inserts a hash if a fragment exists
%a Authority (alias for %u%@%d%:%P)
任何不匹配格式指令的字符都会原样保留：
▶ cat urls.txt | unfurl -u format "%d (%s)"
sub.example.com (https)
example.net (http)
请注意，如果 URL 不包含所请求的数据，该 URL 将不会有输出：
▶ echo http://example.com | unfurl format "%P"
▶ echo http://example.com:8080 | unfurl format "%P"
8080
▶ unfurl -h
Format URLs provided on stdin
Usage:
unfurl [OPTIONS] [MODE] [FORMATSTRING]
Options:
-u, --unique Only output unique values
-v, --verbose Verbose mode (output URL parse errors)
Modes:
keys Keys from the query string (one per line)
values Values from the query string (one per line)
keypairs Key=value pairs from the query string (one per line)
domains The hostname (e.g. sub.example.com)
paths The request path (e.g. /users)
apexes The apex domain (e.g. example.com from sub.example.com)
json JSON encoded url/format objects
format Specify a custom format (see below)
Format Directives:
%% A literal percent character
%s The request scheme (e.g. https)
%u The user info (e.g. user:pass)
%d The domain (e.g. sub.example.com)
%S The subdomain (e.g. sub)
%r The root of domain (e.g. example)
%t The TLD (e.g. com)
%P The port (e.g. 8080)
%p The path (e.g. /users)
%e The path's file extension (e.g. jpg, html)
%q The raw query string (e.g. a=1&b=2)
%f The page fragment (e.g. page-section)
%@ Inserts an @ if user info is specified
%: Inserts a colon if a port is specified
%? Inserts a question mark if a query string exists
%# Inserts a hash if a fragment exists
%a Authority (alias for %u%@%d%:%P)
Examples:
cat urls.txt | unfurl keys
cat urls.txt | unfurl format %s://%d%p?%q