Three methods of string segmentation in shell

Question: For string output such as ' 1,2,3,4,5 ', separate 1 2 3 4 5

Feature: no spaces in string

Workaround 1:

#!/bin/bash
var= ' 1,2,3,4,5 '
var=${var//,/}    #这里是将var中的, replace with space for
element in $var 
do
    echo $ Element done

If there is a space in the original string such as a string such as ' Mark:x:0:0:this is a test user:/var/mark:nologin ', to output the string as delimited, the method above will output the This is a test user separately, which is not correct.

Workaround 2 for this situation:

#!/bin/bash
user= ' mark:x:0:0:this is a test user:/var/mark:nologin ' for
((i=1;i<=7;i++) does
        echo $user |cut-d ":"-f$i done

The above method is to determine the length of the string separated, if the write more general point, to the following

Workaround 3:

#!/bin/bash
user= ' mark:x:0:0:this is a test user:/var/mark:nologin '
i=1 while
((1==1))
do
        split = ' echo $user |cut-d ': '-f$i '
        if [$split '!= ']
        then
                ((i++))
                echo $split else break
        fi Done

This method does not need to know the number of separated strings, and has a better versatility.