update README

Author: ozbillwang

html2txt/Alpine/README.md

@@ -1,11 +1,12 @@
-## convert html file to plain text file
+## Convert html file to plain text file and run html2txt as local command
 
-support the html file `test.html` is at your current folder
+suppose the html file `test.html` is at your current folder
 
 ```
-docker pull bwits/html2txt
-alias html2text="docker run -ti --rm -v $(pwd):/app bwits/html2txt"
-html2txt /app/test.html /app/test.txt
+$ docker pull bwits/html2txt
+$ alias html2txt="docker run -ti --rm -v $(pwd):/app bwits/html2txt"
+$ html2txt /app/test.html /app/test.txt
+$ cat test.txt
 ```
 
 Now you should have the test.txt file generated in current folder