循环逗号分隔的shell变量

Suppose I have a Unix shell variable as below

假设我有一个Unix shell变量，如下所示

variable=abc,def,ghij

I want to extract all the values (abc, def and ghij) using a for loop and pass each value into a procedure.

我想使用for循环提取所有值（abc，def和ghij）并将每个值传递给过程。

The script should allow extracting arbitrary number of comma-separated values from $variable.

该脚本应允许从$ variable中提取任意数量的逗号分隔值。

5 个解决方案

#1

You can use the following script to dynamically traverse through your variable, no matter how many fields it has as long as it is only comma separated.

您可以使用以下脚本动态遍历变量，无论它有多少个字段，只要它只用逗号分隔即可。

variable=abc,def,ghij
for i in $(echo $variable | sed "s/,/ /g")
do
    # call your procedure/other scripts here below
    echo "$i"
done

Instead of the echo "$i" call above, between the do and done inside the for loop, you can invoke your procedure proc "$i".

而不是上面的回声“$ i”调用，在for循环中的do和done之间，你可以调用你的过程proc“$ i”。

---

Update: The above snippet works if the value of variable does not contain spaces. If you have such a requirement, please use one of the solutions that can change IFS and then parse your variable.

更新：如果变量的值不包含空格，则上述代码段有效。如果您有这样的要求，请使用可以更改IFS的解决方案之一然后解析您的变量。

---

Hope this helps.

希望这可以帮助。

#2

Not messing with IFS
Not calling external command

不搞乱IFS不调用外部命令

variable=abc,def,ghij
for i in ${variable//,/ }
do
    # call your procedure/other scripts here below
    echo "$i"
done

Using bash string manipulation http://www.tldp.org/LDP/abs/html/string-manipulation.html

使用bash字符串操作http://www.tldp.org/LDP/abs/html/string-manipulation.html

#3

If you set a different field separator, you can directly use a for loop:

如果设置不同的字段分隔符，则可以直接使用for循环：

IFS=","
for v in $variable
do
   # things with "$v" ...
done

You can also store the values in an array and then loop through it as indicated in How do I split a string on a delimiter in Bash?:

您还可以将值存储在数组中，然后按照如何在Bash中的分隔符上拆分字符串中所示循环它：

IFS=, read -ra values <<< "$variable"
for v in "${values[@]}"
do
   # things with "$v"
done

Test

$ variable="abc,def,ghij"
$ IFS=","
$ for v in $variable
> do
> echo "var is $v"
> done
var is abc
var is def
var is ghij

You can find a broader approach in this solution to How to iterate through a comma-separated list and execute a command for each entry.

您可以在此解决方案中找到更广泛的方法，如何迭代逗号分隔列表并为每个条目执行命令。

Examples on the second approach:

第二种方法的例子：

$ IFS=, read -ra vals <<< "abc,def,ghij"
$ printf "%s\n" "${vals[@]}"
abc
def
ghij
$ for v in "${vals[@]}"; do echo "$v --"; done
abc --
def --
ghij --

#4

#/bin/bash   
TESTSTR="abc,def,ghij"

for i in $(echo $TESTSTR | tr ',' '\n')
do
echo $i
done

I prefer to use tr instead of sed, becouse sed have problems with special chars like \r \n in some cases.

我更喜欢使用tr而不是sed，因为在某些情况下，像\ r \ n这样的特殊字符有问题。

other solution is to set IFS to certain separator

其他解决方案是将IFS设置为某个分隔符

#5

Try this one.

试试这个。

#/bin/bash   
testpid="abc,def,ghij" 
count=`echo $testpid | grep -o ',' | wc -l` # this is not a good way
count=`expr $count + 1` 
while [ $count -gt 0 ]  ; do
     echo $testpid | cut -d ',' -f $i
     count=`expr $count - 1 `
done