`dd` is a command-line utility for Unix-like operating systems, including Linux distributions such as Raspberry Pi OS. It is used for low-level copying and conversion of raw data. Fortunately, `dd` is typically pre-installed on most Unix-like systems, including Raspberry Pi OS.
To check if `dd` is installed, you can simply run it from the command line:
```sh
dd --version
```
If `dd` is not installed (which is unlikely), you can install it by ensuring that the `coreutils` package is installed, as `dd` is a part of this package. Here’s how to install it:
1. **Update the package list:**
```sh
sudo apt update
```
2. **Install `coreutils`:**
```sh
sudo apt install coreutils
```
3. **Verify the installation:**
```sh
dd --version
```
This should ensure that `dd` is installed and ready to use on your Raspberry Pi.
`dd` is a powerful command-line tool used for copying and converting data. Below are some common use cases and examples to help you get started:
### Basic Syntax
```sh
dd if=[source] of=[destination] [options]
```
- `if`: Input file or source.
- `of`: Output file or destination.
- `[options]`: Various options to control the behavior of `dd`.
### Common Use Cases
#### 1. **Create a Bootable SD Card**
To write an image file to an SD card:
```sh
sudo dd if=path/to/image.img of=/dev/sdX bs=4M status=progress
```
- `if=path/to/image.img`: Path to the input image file.
- `of=/dev/sdX`: Replace `/dev/sdX` with the actual device name of your SD card.
- `bs=4M`: Sets the block size to 4MB (adjust as needed).
- `status=progress`: Displays the progress of the operation.
#### 2. **Backup an SD Card**
To create an image file from an SD card:
```sh
sudo dd if=/dev/sdX of=path/to/backup.img bs=4M status=progress
```
- `if=/dev/sdX`: Replace `/dev/sdX` with the device name of your SD card.
- `of=path/to/backup.img`: Path where the backup image will be saved.
#### 3. **Wipe a Disk**
To completely wipe a disk by overwriting it with zeros:
```sh
sudo dd if=/dev/zero of=/dev/sdX bs=4M status=progress
```
- `if=/dev/zero`: Uses `/dev/zero` as the source, which provides an infinite stream of zeros.
- `of=/dev/sdX`: Replace `/dev/sdX` with the device name of the disk you want to wipe.
#### 4. **Clone a Disk**
To clone one disk to another:
```sh
sudo dd if=/dev/sdX of=/dev/sdY bs=4M status=progress
```
- `if=/dev/sdX`: Source disk.
- `of=/dev/sdY`: Destination disk.
#### 5. **Convert and Copy a File**
To convert text to uppercase while copying:
```sh
dd if=input.txt of=output.txt conv=ucase
```
- `conv=ucase`: Converts text to uppercase.
### Additional Options
- `bs=[size]`: Block size. E.g., `bs=1M` sets block size to 1MB.
- `count=[number]`: Number of blocks to copy.
- `skip=[number]`: Number of blocks to skip from the input file.
- `seek=[number]`: Number of blocks to skip in the output file.
### Example Commands
1. **Create a 1GB file filled with zeros:**
```sh
dd if=/dev/zero of=output.img bs=1M count=1024
```
2. **Measure Write Speed:**
```sh
dd if=/dev/zero of=output.img bs=1M count=1024 oflag=dsync
```
3. **Create a Backup of a Partition:**
```sh
sudo dd if=/dev/sda1 of=backup.img bs=4M status=progress
```
4. **Restore a Backup to a Partition:**
```sh
sudo dd if=backup.img of=/dev/sda1 bs=4M status=progress
```
### Safety Tips
- Always double-check the `if` and `of` parameters to avoid accidental data loss.
- Use the `status=progress` option to monitor the progress of the `dd` operation.
- Consider using tools like `rsync` or `partclone` for more user-friendly backup and cloning operations.
By mastering these commands and options, you can effectively utilize `dd` for various data manipulation tasks on your Raspberry Pi or any Unix-like system.
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