Checking Syntax in Bash
This article discusses methods for checking Bash scripts for syntax problems without running the script.
Syntax errors are caused by some grammatical or spelling mistakes in the code. In modern compilers of other programming languages, the compiler highlights such errors even before running the program.
This is not the case in Bash scripts, since Bash is a command line interpreter. Hence, we need to check for syntax errors separately.
There are different techniques to check for syntax issues as shown below.
Using the Online ShellCheck Editor
There is an online tool Shell Check that can check the syntax errors of the script.
In the above picture, there are two separate windows. One is the code editor, and the lower part shows a list of errors and warnings in the code by specifying line numbers.
ShellCheck Editor is a very useful tool for both beginner and expert programmers as it detects minor to advanced issues in the code before executing it.
Use bash -n (noexec mode) command
You can also use the -n flag (noexec) with the bash command to check for errors in your scripts.
bash -n [script-name]
This will just read all the commands in the script and check for errors without running them. If there are errors in the commands, it will show them; otherwise, no output will be shown.
For example, consider the following script.
请注意, we have missed the end of the if statement (i.e., used fi instead of if). So, it will give an error.
Using sh command
Another command to check for syntax errors is:
sh -n [script-name]
We will run the command for the same script discussed in the previous section and check for errors.
For reprinting, please send an email to 1244347461@qq.com for approval. After obtaining the author's consent, kindly include the source as a link.
Related Articles
How to decompress x.tar.xz format files under Linux
Publish Date：2025/04/08 Views：186 Category：OPERATING SYSTEM
-
A lot of software found today is in the tar.xz format, which is a lossless data compression file format that uses the LZMA compression algorithm. Like gzip and bzip2, it supports multiple file compression, but the convention is not to compr
Summary of vim common commands
Publish Date：2025/04/08 Views：115 Category：OPERATING SYSTEM
-
In Linux, the best editor should be vim. However, the complex commands behind vim's powerful functions also make us daunted. Of course, these commands do not need to be memorized by rote. As long as you practice using vim more, you can reme
Detailed explanation of command return value $? in Linux
Publish Date：2025/04/08 Views：58 Category：OPERATING SYSTEM
-
? is a special variable. This variable represents the return value of the previous command. That is to say, when we run certain commands, these commands will return a code after running. Generally, if the command is successfully run, the re
Common judgment formulas for Linux script shell
Publish Date：2025/04/08 Views：159 Category：OPERATING SYSTEM
-
In shell script programming, predicates are often used. There are two ways to use predicates, one is to use test, and the other is to use []. Let's take a look at how to use these two methods through two simple examples. Example 1 # test –
Shell script programming practice - specify a directory to delete files
Publish Date：2025/04/08 Views：98 Category：OPERATING SYSTEM
-
Usually, in Linux system we need to frequently delete some temporary files or junk files. If we delete them one by one manually, it will be quite troublesome. I have also been learning shell script programming recently, so I tried to write
Use of Linux command at - set time to execute command only once
Publish Date：2025/04/08 Views：158 Category：OPERATING SYSTEM
-
This article mainly involves a knowledge point, which is the atd service. Similar to this service is the crond service. The functions of these two services can be similar to the two functional functions of javascript. Those who have learned
Use of Linux command crontab - loop execution of set commands
Publish Date：2025/04/08 Views：170 Category：OPERATING SYSTEM
-
Compared with at , which executes a command only once, crontab, which we are going to talk about in this article, executes the set commands in a loop. Similarly, the use of crontab requires the support of the crond service. The service is s
Linux practice - regularly delete files under the directory
Publish Date：2025/04/08 Views：198 Category：OPERATING SYSTEM
-
Since we want to delete the files under the directory regularly, we need to use the Linux crontab command. And the content format of each work routine is also introduced in the format of each crontab work. Similarly, we need to use shell sc
How to use the Linux file remote copy command scp
Publish Date：2025/04/08 Views：151 Category：OPERATING SYSTEM
-
Scp copies files between two hosts over the network, and the data is encrypted during transmission. Its underlying layer uses ssh for data transmission. And it has the same authentication mechanism and the same security level as ssh. When u
