> For the complete documentation index, see [llms.txt](https://linux-tutorial-cli.gitbook.io/linux-cli-tutorial/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://linux-tutorial-cli.gitbook.io/linux-cli-tutorial/txt-files/rev.md).

# rev

## rev

The `rev` command in Linux is used to reverse the order of characters in a file or string. It is a simple command that can be used for a variety of tasks, such as reversing the order of words in a sentence or reversing the order of lines in a file.

The `rev` command is used in the following syntax:

```
rev [options] [file]
```

The `file` is the file to reverse. If no file is specified, the standard input will be reversed.

The `options` can be used to specify the following:

* The number of lines to reverse.
* The character to use as the delimiter between reversed lines.

For example, to reverse the order of lines in the file `myfile`, you would use the following command:

```
rev myfile
```

This command will reverse the order of lines in the file `myfile` and print the results to the standard output.

The `rev` command is a simple but powerful command that can be used for a variety of tasks. It is supported by most Linux distributions and is a useful tool for reversing the order of characters in files or strings.

Here are some examples of how to use the `rev` command:

* To reverse the order of words in a sentence, you can use the following command:

```
rev "Hello world!"
```

This command will reverse the order of words in the sentence "Hello world!" and print the results to the standard output:

```
!dlrow olleH
```

* To reverse the order of lines in a file, you can use the following command:

```
rev myfile
```

This command will reverse the order of lines in the file `myfile` and print the results to the standard output.

* To reverse the order of characters in a string, you can use the following command:

```
rev "This is a string."
```

This command will reverse the order of characters in the string "This is a string." and print the results to the standard output:

```
.gnirts a si sihT
```

The `rev` command is a versatile tool that can be used for a variety of tasks. It is a simple command to use and is supported by most Linux distributions.

## help

```
```