You would like to type some sensitive information in the command line (password, key), but you don’t want this to appear in the history.
Add a single space before the start of the command.
Problem
You would like to quickly convert a number from a different base system (i.e. binary, octal, hexadecimal), to decimal.
Solution
Use the echo $(()) shell command to convert it passing it the current base system and the number, as in $((2#101010)) or using the O for octal or 0x for hexadecimal notations.
Examples:
echo $(( 16#FF )) 255 echo $(( 0xFF )) 255 echo $(( 8#21 )) 17 echo $(( 021 )) 17
Taken from Linux Journal’s Work the Shell column (March 2016)
Problem
After a new rvm installation in an (k)ubuntu system you get the following error from rvm when trying to switch between rubies:
You need to change your terminal emulator preferences to allow login shell. Sometimes it is required to use `/bin/bash --login` as the command. Please visit https://rvm.io/integration/gnome-terminal/ for a example.
Solution
As the message suggests you can change the setting in your terminal which is fine if you are using the gnome-terminal by going to the link provided:
Please visit https://rvm.io/integration/gnome-terminal/ for a example.
but if you are using Konsole in KDE you need to go to a different link that explains the change in the settings:
Please visit http://rvm.io/integration/konsole/ for a example.