stdin,stdoutpup, Go & life at the command-line
stdin,stdoutpup, Go & life at the command-line
$ cd ~/talks/codementor$ cat hello.txtHello, Code Mentor!$
CLI life: Data
data
[LOG] some data[LOG] more data[LOG] even more
col1,col2,col3some,data,andeven,more,data
{ “some”: “data”, “more”: “data”}
<div>
<h1>Some</h1><p>data</p>
</div>
grep & nl
grep
cat
grep
cat
pipes!
$ cat Shakespeare.txt | \ sed -e 's/\s+/\n/g' | \ tr -d ' ' | \ grep -e '^$' -v | \ tr '[:upper:]' '[:lower:]' | \ sort | uniq -c | sort -nr | \ head -n 50
$ cat Shakespeare.txt | \ sed -e 's/\s+/\n/g' | \ tr -d ' ' | \ grep -e '^$' -v | \ tr '[:upper:]' '[:lower:]' | \ sort | uniq -c | sort -nr | \ head -n 50
$ cat Shakespeare.txt | \ sed -e 's/\s+/\n/g' | \ tr -d ' ' | \ grep -e '^$' -v | \ tr '[:upper:]' '[:lower:]' | \ sort | uniq -c | sort -nr | \ head -n 50
$ cat Shakespeare.txt | \ sed -e 's/\s+/\n/g' | \ tr -d ' ' | \ grep -e '^$' -v | \ tr '[:upper:]' '[:lower:]' | \ sort | uniq -c | sort -nr | \ head -n 50
$ cat Shakespeare.txt | \ sed -e 's/\s+/\n/g' | \ tr -d ' ' | \ grep -e '^$' -v | \ tr '[:upper:]' '[:lower:]' | \ sort | uniq -c | sort -nr | \ head -n 50
$ cat Shakespeare.txt | \ sed -e 's/\s+/\n/g' | \ tr -d ' ' | \ grep -e '^$' -v | \ tr '[:upper:]' '[:lower:]' | \ sort | uniq -c | sort -nr | \ head -n 50
$ cat Shakespeare.txt | \ sed -e 's/\s+/\n/g' | \ tr -d ' ' | \ grep -e '^$' -v | \ tr '[:upper:]' '[:lower:]' | \ sort | uniq -c | sort -nr | \ head -n 50
$ cat Shakespeare.txt | \ sed -e 's/\s+/\n/g' | \ tr -d ' ' | \ grep -e '^$' -v | \ tr '[:upper:]' '[:lower:]' | \ sort | uniq -c | sort -nr | \ head -n 50
$ cat Shakespeare.txt | \ sed -e 's/\s+/\n/g' | \ tr -d ' ' | \ grep -e '^$' -v | \ tr '[:upper:]' '[:lower:]' | \ sort | uniq -c | sort -nr | \ head -n 50
$ cat Shakespeare.txt | \ sed -e 's/\s+/\n/g' | \ tr -d ' ' | \ grep -e '^$' -v | \ tr '[:upper:]' '[:lower:]' | \ sort | uniq -c | sort -nr | \ head -n 50
curl & wget
$ wget -O Shakespeare.txt \ http://gutenberg.org/cache/epub/100/pg100.txt
$ wget -O Shakespeare.txt \ http://gutenberg.org/cache/epub/100/pg100.txt
$ wget -O Shakespeare.txt \ http://gutenberg.org/cache/epub/100/pg100.txt
wget =
$ wget --load-cookies cookies.txt
$ wget -O Shakespeare.txt \ http://gutenberg.org/cache/epub/100/pg100.txt
$ curl -o Shakespeare.txt \ http://gutenberg.org/cache/epub/100/pg100.txt
$ cat Shakespeare.txt | \ sed -e 's/\s+/\n/g' | \ tr -d ' ' | \ grep -e '^$' -v | \ tr '[:upper:]' '[:lower:]' | \ sort | uniq -c | sort -nr | \ head -n 50
$ curl http://gutenberg.org... | \ sed -e 's/\s+/\n/g' | \ tr -d ' ' | \ grep -e '^$' -v | \ tr '[:upper:]' '[:lower:]' | \ sort | uniq -c | sort -nr | \ head -n 50
curl & wget
curl & wget
I hate HTML
HTML is really hard
“Every time you attempt to parse HTML with regular expressions, the unholy child weeps the blood of virgins, and Russian hackers pwn your webapp.”
“Have you tried using an XML parser instead?”
But it gets worse
<tbody> <tr><img src="foo"></tr> <tr><img/><br> </tbody></table>
<tbody> <tr><img src="foo"></tr> <tr><img/><br> </tbody></table>
Yes, this is valid HTML:
<tbody> <tr><img src="foo"></tr> <tr><img/><br> </tbody></table>
Yes, this is valid HTML:
<tbody> <tr><img src="foo"></tr> <tr><img/><br> </tbody></table>
Yes, this is valid HTML:
<tbody> <tr><img src="foo"></tr> <tr><img/><br> </tbody></table>
Yes, this is valid HTML:
NEVER TRY TO WRITE AN HTML PARSER
pup
Still HTML
$ curl -L -s reddit.com/r/programming/ | \ pup p.title a[href^=http] attr{href}
$ curl -s https://news.ycombinator.com/ | \ pup td.title a[href^=http] attr{href}
$ curl -L -s reddit.com/r/programming/ | \ pup p.title a[href^=http] attr{href}
$ curl -s https://news.ycombinator.com/ | \ pup td.title a[href^=http] attr{href}
$ curl -L -s reddit.com/r/programming/ | \ pup p.title a[href^=http] attr{href}
$ curl -s https://news.ycombinator.com/ | \ pup td.title a[href^=http] attr{href}
$ curl -L -s reddit.com/r/programming/ | \ pup p.title a[href^=http] attr{href}
$ curl -s https://news.ycombinator.com/ | \ pup td.title a[href^=http] attr{href}
$ curl -s https://news.ycombinator.com/ | \ pup td.title a[href^=http] json{}[ { "attrs": { "href": "https://hacks.mozilla.org/2014/10/passwordless-authentication-secure-simple-and-fast-to-deploy/" }, ...]
$ curl -s https://news.ycombinator.com/ | \ pup td.title a[href^=http] json{}[ { "attrs": { "href": "https://hacks.mozilla.org/2014/10/passwordless-authentication-secure-simple-and-fast-to-deploy/" }, ...]
$ curl -s https://news.ycombinator.com/ | \ pup td.title a[href^=http] json{}[ { "attrs": { "href": "https:.../" }, "tag": "a", "text": "SHOW HN: pup" }, ...]
github.com/EricChiang/pup
Part II: Building CLI tools in Go
import java.util.Scanner;
class Hello { public static void main(String[] args) { Scanner reader = new Scanner(System.in); System.out.print("Enter your name: "); String name = reader.nextLine(); System.out.printf("Hello, "+name+"!"); }}
import java.util.Scanner;
class Hello { public static void main(String[] args) { Scanner reader = new Scanner(System.in); System.out.print("Enter your name: "); String name = reader.nextLine(); System.out.printf("Hello, "+name+"!"); }}
import java.util.Scanner;
class Hello { public static void main(String[] args) { Scanner reader = new Scanner(System.in); System.out.print("Enter your name: "); String name = reader.nextLine(); System.out.printf("Hello, "+name+"!"); }}
import java.util.Scanner;
class Hello { public static void main(String[] args) { Scanner reader = new Scanner(System.in); System.out.print("Enter your name: "); String name = reader.nextLine(); System.out.printf("Hello, "+name+"!"); }}
Why Go?
Why not?
Taken from Rob Pike’s talk public static void main (2012)
Taken from Rob Pike’s talk public static void main (2012)
“dear god make it stop”
Why not?
Why not?
I suck at this -->
Go
package main
import "fmt"
func main() {fmt.Println("Hello, world!")
}
line
package main
import "io"import "os"
func main() {io.Copy(os.Stdout, os.Stdin)io.WriteString(os.Stdout, "\n")
}
package main
import "io"import "os"
func main() {io.Copy(os.Stdout, os.Stdin)io.WriteString(os.Stdout, "\n")
}
package main
import "io"import "os"
func main() {io.Copy(os.Stdout, os.Stdin)io.WriteString(os.Stdout, "\n")
}
package main
import "io"import "os"
func main() {io.Copy(os.Stdout, os.Stdin)io.WriteString(os.Stdout, "\n")
}
package main
import "io"import "os"
func main() {io.Copy(os.Stdout, os.Stdin)io.WriteString(os.Stdout, "\n")
}
$ echo "Hello, World"Hello, World
$ echo "Hello, World"Hello, World$ go get github.com/ericchiang/line
$ echo "Hello, World"Hello, World$ go get github.com/ericchiang/line$ echo "Hello, World" | lineHello, World
$
url-encode
Live demo!
gox
Messing with zip
Thanks!
Recommended
