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How To Fix “Syntax Error Near Unexpected Token ‘(‘” When Running a Shell Script with rm Command

Ubuntu 10

If you’re working with shell scripts, you may have encountered the error “Syntax Error Near Unexpected Token ‘(‘” when trying to run a script with the rm command. This error is usually caused by the shell not recognizing the extglob syntax, a feature that allows for advanced pattern matching. In this article, we will discuss how to fix this error and successfully run your shell script.

Quick Answer

To fix the "Syntax Error Near Unexpected Token ‘(‘" when running a shell script with the rm command, you can either enable the extglob option in your script by adding shopt -s extglob at the beginning, or use the GLOBIGNORE variable to exclude files with a specific extension from being removed.

Understanding the Error

Before we delve into the solution, it’s important to understand the cause of the error. The !(*.sh) syntax is part of the extglob feature in Bash. This syntax allows you to match all files except those with a specific extension, in this case, .sh. However, extglob is not enabled by default in shell scripts, causing the shell to throw a syntax error when it encounters the !(*.sh) syntax.

Enabling extglob

One solution to this error is to enable the extglob option in your shell script. You can do this by adding the following line at the beginning of your script:

shopt -s extglob

The shopt command is used to toggle the values of shell options. The -s option stands for “set”, meaning that it enables the option that follows. In this case, it enables extglob.

Here’s an updated version of your clean.sh script:

#!/bin/bash
shopt -s extglob
rm !(*.sh) -rf

The rm command is used to remove files or directories. The -r or -R option tells rm to remove directories and their contents recursively, and the -f option forces deletion of files without prompting for confirmation.

Using GLOBIGNORE

If you don’t want to enable extglob, you can use the GLOBIGNORE variable to achieve the same result. GLOBIGNORE is a bash variable that defines the patterns that should be ignored during pathname expansion.

Here’s an example:

#!/bin/bash
GLOBIGNORE='*.sh'
rm -rf *

In this case, the GLOBIGNORE variable is set to exclude files with the .sh extension from glob expansion, and then the rm command is used to remove all remaining files.

Conclusion

Both of these solutions should allow you to remove all files except those with the .sh extension when running your shell script. Remember to always be careful when using the rm command, especially with the -r and -f options, as it can permanently delete files.

For more information on shell scripting and the rm command, you can refer to the GNU Bash Manual and the rm command man page.

What is a shell script?

A shell script is a computer program written in a scripting language that is interpreted by a shell, such as Bash. It contains a series of commands that are executed in sequence.

How do I run a shell script?

To run a shell script, you need to make it executable using the chmod command. For example, you can use chmod +x script.sh to make the script named "script.sh" executable. Then, you can run it by typing ./script.sh in the terminal.

How can I debug a shell script?

There are several ways to debug a shell script. One common approach is to use the set -x command at the beginning of your script to enable debugging mode. This will print each command and its arguments before executing them. You can also use the echo command to print variable values or intermediate results to the terminal for debugging purposes.

How can I pass arguments to a shell script?

You can pass arguments to a shell script by providing them after the script name when running it. For example, if your script is named "script.sh" and you want to pass two arguments, you can run it like this: ./script.sh arg1 arg2. Inside the script, you can access these arguments using positional parameters like $1, $2, etc.

How can I redirect the output of a shell script to a file?

You can redirect the output of a shell script to a file using the > operator. For example, if you want to redirect the output to a file named "output.txt", you can run the script like this: ./script.sh > output.txt. This will overwrite the contents of the file. If you want to append the output to an existing file, you can use the >> operator instead: ./script.sh >> output.txt.

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