df:tldr:eea7f
The command "df" (disk free) is used in Unix-like operating systems to display the amount of free and used disk space on a filesystem.
In this specific command, the "-x" option is used to exclude specific filesystem types from the output. It is followed by two arguments enclosed in "${ }", which are variables.
The first variable "${squashfs}" is expected to contain the name of a filesystem type that needs to be excluded from the output. The "squashfs" filesystem type is commonly used for read-only compressed file systems.
The second variable "${tmpfs}" is expected to contain the name of another filesystem type to be excluded. "tmpfs" is typically used for creating a temporary file system in memory.
By using "-x" followed by the two variables, this command effectively excludes any filesystem type named "squashfs" or "tmpfs" from the output of the "df" command.