How to use rsync command on Linux/Unix with examples

From the man page of rsync, Rsync is a fast and extraordinarily versatile file copying tool. It can copy locally, to/from another host over any remote shell, or to/from a remote rsync daemon. It offers a large number of options that control every aspect of its behavior and permit very flexible specification of the set of files to be copied. It is famous for its delta-transfer algorithm, which reduces the amount of data sent over the network by sending only the differences between the source files and the existing files in the destination.

Source: How to use rsync command on Linux/Unix with examples – Computing for Geeks

Doing Date Math on the Command Line, Parts I & II | Linux Journal

If you’ve ever used a spreadsheet, you’ve probably used or seen functions for doing date math—in other words, taking one date and adding some number of days or months to it to get a new date, or taking two dates and finding the number days between them. The same thing can be done from the command line using the lowly date command, possibly with a little help from Bash’s arithmetic.

Source: Doing Date Math on the Command Line, Part I | Linux Journal

Source: Doing Date Math on the Command Line – Part II | Linux Journal