About bash builtin command named “test”

ABOUT test test provides no output, but returns 0 for “true” (test successful) and 1 for “false” (test failed). RELATED COMMAND LINE EXPOSURE LINK https://www.computerhope.com/unix/bash/test.htm

Fundamentals related to bash builtin command named “shift”

ABOUT shift shift [n] The positional parameters from n+1 … are renamed to $1 …. Parameters represented by the numbers $# down to $#-n+1 are unset. n must be a non-negative number less than or equal to $#. If n is 0, no parameters are changed. If n is not given, it is assumed to

Understanding bash fundamentals and also about return command

ABOUT return Causes a function to stop executing and return the value specified by n to its caller. If n is omitted, the return status is that of the last command executed in the function body. TYPICAL COMMAND LINE EXPOSURE LINKS https://ryanstutorials.net/bash-scripting-tutorial/bash-functions.php https://stackoverflow.com/questions/4419952/difference-between-return-and-exit-in-bash-functions

About bash builtin command named “eval”

ABOUT eval eval is a builtin command of the Bash shell. It concatenates its arguments into a single string, joining the arguments with spaces, then executes that string as a bash command. It’s similar to running bash -c “string”, but eval executes the command in the current shell environment rather than creating a child shell

Learning D-Bus

https://www.freedesktop.org/wiki/Software/dbus/ https://www.freedesktop.org/wiki/IntroductionToDBus/ https://www.packtpub.com/mapt/book/application_development/9781849519427/10/ch10lvl1sec126/time-for-action–listening-to-d-bus https://dbus.freedesktop.org/doc/dbus-specification.html https://stackoverflow.com/questions/2830858/controlling-gnome-volume-using-dbus https://dbus.freedesktop.org/doc/dbus-tutorial.html#concepts https://dbus.freedesktop.org/doc/diagram.svg https://developer.gnome.org/NetworkManager/stable/spec.html https://developer.gnome.org/NetworkManager/stable/gdbus-org.freedesktop.NetworkManager.html http://www.beautifulwork.org/wp-content/uploads/2018/11/dbus.pdf http://www.beautifulwork.org/wp-content/uploads/2018/11/dbus.docx