How to convert a string with hidden characters to a normal string

Question

Does anyone have an idea on how to remove hidden characters from a string in the shell?

• This is an example :

  # echo $a;
  [root@localhost ~]#
  

• But when I "force" display of hidden characters it looks like this:

  # echo $a | cat -v
  [root@localhost ~]# ls ^H^[[K^H^[[K^H^[[Kpwd^H^[[K^H^[[K^H^[[Kls^H^[[K^H^[[Kpwd^H^[[K^H^[[K^H^[[K
  

• I want to delete hidden characters to have this output:

  # echo $a | cat -v
  [root@localhost ~]#
  

Answer 1

Use sed to strip out the non-printing characters:

echo $a | sed 's/[^ -~]//g' | cat -v

Or to store it:

a=$(echo $a | sed 's/[^ -~]//g')