zdiff:tldr:9eedc

The command "zdiff ${filename1-gz} ${filename2-gz}" is used to compare the contents of two compressed (gzipped) files.

Here's a breakdown of the command:

• "zdiff" is the name of the command or utility being executed.
• "${filename1-gz}" and "${filename2-gz}" are the names of the input files you want to compare. These variables should be replaced with the actual filenames (including the .gz extension) when running the command.
• The "-gz" extension in the filenames suggests that the files are compressed using gzip compression. If the files were not compressed with gzip, the command may not work properly.

When the command is executed, zdiff will decompress the files, compare their contents, and display the differences between them (if any). The differences may include added or removed lines, modified lines, or changes in the file structure. If the files are identical, no output will be displayed.