expand:tldr:31407
The command "expand" is used in various operating systems and software programs to convert tabs in a file into spaces or to shrink consecutive spaces into tabs.
In some cases, "expand" is used to convert tabs into a defined number of spaces. For example, if a text file contains tabs that are set to be equal to 4 spaces, the command "expand -t4 filename.txt" will replace all tabs with 4 spaces each.
Conversely, "expand" can also be used to convert a specified number of spaces into tabs. For instance, if a text file contains 4 consecutive spaces, the command "expand -t4 filename.txt" will replace those spaces with a single tab character.
The "expand" command is particularly useful when working with files that are required to have a specific spacing or when maintaining consistent formatting across different platforms or programs.