Termux is a terminal emulator for Android and a minimalistic GNU / Linux environment. Termux installs a minimum default base system allowing additional applications to be installed using the apt package manager. Termux does not need your phone to be rooted to run.
Rsync is a fast and versatile file synchronization tool that allows to copy and sync files locally and from rsync service or any device that supports remote shell (Rsync does not support synchronization between remote devices). Rsync offers a large number of options that control every aspect of its behaviour and permit very flexible specification of the set of files to be copied.
If your console (terminal) is in a state where you don't see what you write because of an aborted ssh session or it is showing unreadable characters after trying to open a binary, this can be solved by typing the command:
To refresh the aliases defined in .bashrc run:
$ source .bashrc
$ exec bash
grep is a command-line utility that allows searching of words and/or patterns in a file or group of files. Its name comes from the ed command g/re/p (globally search a regular expression and print). Grep does a global search by keyword or regular expression and print all matching lines on the standard output.