swapon:tldr:5e1eb

The command "swapon ${-dev-sdb7}" is incorrect syntax. It seems like an attempt to activate a swap partition or file in Linux using the "swapon" command.

Here's the correct syntax to activate a swap partition or file using the "swapon" command:

1. For a swap partition:

   swapon /dev/sdb7

   In this command, "/dev/sdb7" is the path to the swap partition you want to activate.

2. For a swap file:

   swapon /path/to/swap/file

   In this command, "/path/to/swap/file" is the path to the swap file you want to activate.

Remember to replace "/dev/sdb7" or "/path/to/swap/file" with the appropriate path for your system. Also, make sure you have the necessary permissions to use the "swapon" command, such as running it as the root user or using the "sudo" command.