Linux Shell learning comes in mind

The Magical magic of awk:

Extract the number 600 and note the special effect of the + sign.

echo "Fuck 600ms" |awk ' {print + $NF} '

Result: Other characters are filtered, leaving only the number 600

Using If,for in Commad mode

#测试if

a=200

if [$a = =];then echo "A is $a"; fi

# #测试for Loop

For x in "Cat" "Dog" "Pig";d o echo $x;d one

# #排除bzezt的文件, the other output size.

For dir in ' ls./';d o if [$dir! = "Bzezt"]; Then Du-sh $dir; Fi done

Summary: A non-keyword statement block ends and must be separated by semicolons, which is equivalent to a line in a shell script. If it is a keyword, you can add it without a semicolon.

This article is from the "Cool bit Linux" blog, so be sure to keep this source http://coolbyte.blog.51cto.com/8289854/1690824

Linux Shell learning comes in mind