[手动选题][tech]: 20230717.0 ⭐️⭐️ Bash Basics Series 6 Handling String Operations.md

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+[#]: subject: "Bash Basics Series #6: Handling String Operations"
+[#]: via: "https://itsfoss.com/bash-strings/"
+[#]: author: "Abhishek Prakash https://itsfoss.com/author/abhishek/"
+[#]: collector: "lkxed"
+[#]: translator: " "
+[#]: reviewer: " "
+[#]: publisher: " "
+[#]: url: " "
+
+Bash Basics Series #6: Handling String Operations
+======
+
+In most programming languages, you'll find a string data type. A string is basically a group of characters.
+
+Bash shell is different though. There is no separate data type for strings. Everything is a variable here.
+
+But that doesn't mean that you cannot deal with strings in the same way you do in C and other programming languages.
+
+Finding substrings, replacing substrings, joining strings and many more string operations are possible in Bash shell.
+
+In this part of the Bash Basics Series, you'll learn the basic string manipulations.
+
+### Get string length in bash
+
+Let's start with the simplest option. Which is to get the length of a string. It's quite simple:
+
+```
+${#string}
+```
+
+Let's use it in an example.
+
+![Example of getting string length in bash][1]
+
+As you can see, the second example had two words in it but since it was in quotes, it was treated as a single word. Even the space is counted as a character.
+
+### Join strings in bash
+
+The technical term is concatenation of strings, one of the simplest possible string operations in bash.
+
+You just have to use the string variables one after another like this:
+
+```
+str3=$str1$str2
+```
+
+Can it go any simpler than this? I don't think so.
+
+Let's see it with an example. Here is my example script named `join.sh`:
+
+```
+#!/bin/bash
+
+read -p "Enter first string: " str1
+read -p "Enter second string: " str2
+
+joined=$str1$str2
+
+echo "The joined string is: $joined"
+```
+
+Here's a sample run of this script:
+
+![Join two strings in bash][2]
+
+### Extract substring in bash
+
+Let's say you have a big string with several characters and you want to extract part of it.
+
+To extract a substring, you need to specify the main string, the starting position of the substring and the length of the substring in the following manner:
+
+```
+${string:$pos:$len}
+```
+
+> 💡Like arrays, positioning in strings also start at 0.
+
+Here's an example:
+
+![Extracting substring in bash][3]
+
+Even if you specify the substring length greater than the string length, it will only go till the end of the string.
+
+### Replace substring in bash
+
+Let's say you have a big string and you want to replace part of it with another string.
+
+In that case, you use this kind of syntax:
+
+```
+${string/substr1/substr2}
+```
+
+> ✋ Only the first occurrence of a substring is replaced this way. If you want to replace all occurrences, use`${string//substr1/substr2}`
+
+Here's an example:
+
+![Replace substring in bash][4]
+
+As you can see above, the word good was replaced with best. I saved the replaced string to the same string to change the original.
+
+> 💡 If the substring is not found, nothing is replaced. It won't result in an error.
+
+### Delete substring in bash
+
+Let's talk about removing substrings. Let's say you want to remove part of a string. In that case, just provide the substring to the main string like this:
+
+```
+${string/substring}
+```
+
+> ✋ Only the first occurrence of a substring is deleted this way. If you want to delete all occurrences, use`${string//substr}`
+
+If the substring is found, it will be deleted from the string.
+
+Let's see this with an example.
+
+![Delete substring in bash][5]
+
+This goes without saying that if the substring is not found, it is not deleted. It won't result in an error.
+
+### 🏋️ Exercise time
+
+It's time for you to practice string manipulation with simple exercises.
+
+**Exercise 1**: Declare a string 'I am all wet'. Now change this string by replacing the word wet with set.
+
+**Exercise 2**: Create a string that saves phone numbers in the following format `112-123-1234`. Now, you have to delete all `-`.
+
+That should give you some decent practice with strings in bash. In the next chapter, you'll learn about using if-else statements in bash. Stay tuned.
+
+--------------------------------------------------------------------------------
+
+via: https://itsfoss.com/bash-strings/
+
+作者：[Abhishek Prakash][a]
+选题：[lkxed][b]
+译者：[译者ID](https://github.com/译者ID)
+校对：[校对者ID](https://github.com/校对者ID)
+
+本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
+
+[a]: https://itsfoss.com/author/abhishek/
+[b]: https://github.com/lkxed/
+[1]: https://itsfoss.com/content/images/2023/07/bash-string-length-example.png
+[2]: https://itsfoss.com/content/images/2023/07/join-strings-bash.png
+[3]: https://itsfoss.com/content/images/2023/07/extract-substring-bash.png
+[4]: https://itsfoss.com/content/images/2023/07/replace-substring-bash.png
+[5]: https://itsfoss.com/content/images/2023/07/bash-delete-substring.png