Split string in Shell

Recently the system has learned shell programming.

See an example in the book, very dick. I thought about it before, but I didn't get the result.

I believe that the students also guessed this example, is a line of string splitting. Students can try it out before they see the answer.

Here I have summed up three ways. For reference only.

1. First of all, of course, the contents of the book:

echo JALSDFJLASJDL | Sed "s/[^\n]/&\n/g"

The output of this example is to separate each character nonalphanumeric into a single line.

SED statement believe that the students are not unfamiliar. The only thing that can be confusing is the use of & symbols. In fact, the combination of this sentence, can also understand. Replaces the smallest unit of the previous match. [^\n] matches any character that is not a newline. The smallest unit is naturally a single character.

2. Use the string extension. The code is as follows:

#!/bin/bashstr= "Love your Jingjing" for i in ' seq ${#str} ' Doecho ${str: $i -1;1}done

In this code, the expansion of curly braces is used. The first ${#str}. Represents the length of Str. The second ${str: $i -1:1} means to take the 1 characters of the i-1 position of the STR string.

So the printing here naturally also prints each character by line. I don't know how to explain why I write $i-1 directly. I thought it would be an error.

3. Use awk. This is also not entirely their own thinking. It is also summarized by reference to the data.

echo "Love Jingjing" | Awk-f "" ' {for (i=1;i<=nf;i++) {print $i}} '

In fact, it's not hard to really understand the code of AWK. The difficulty is that I don't know "" "two double quotes next to each other is no delimiter, so-called No, that is, empty is the delimiter. That's a mouthful.

Understanding this point, the rest of the content can be understood.

is not beginning to associate. Split into two or more how to get.

How to sed: Echo alksfdjals | Sed "s/[^\n]\{2\}/&\n/g"

How to extend the string:

#!/bin/bash-xalai= "Love-Jingjing" for ((i=0; $i <=${#alai};i= $i +2));d o     echo ${alai: $i: 2};d One

This code uses the special use of parentheses, that is, two parentheses attached, you can freely do the operation. I am personally beautiful in the name of the C language form.

Summed up such a few ideas for a few days, and are not independent thinking, are more or less borrowed from others or books above the idea. Although digested. But it's a bit lacking in the spirit of independence.

After reading this article, students have their own different ideas

Split string in Shell