How to assign a variable the sed command with formatting? Shellscript

Question

I’m having a problem making a program to exchange the first number for X, because even if it works, the variable does not receive the value permanently:

VAR="oi                                 200          20   10"
VAR= echo "$VAR" | sed -r -n "s/[0-9]+/X/p"
echo $VAR

It’s coming off:

oi                                 X          20   10
oi 200 20 10

I would like to know how to get the variable to permanently receive the exchange of the first number by X, and how to get the same formatting, because sed ignores the spaces I gave and puts only one in place. I wish the way out:

oi                                 X          20   10
oi                                 X          20   10

Answer 1

To assign the result of a command to a variable has two options:

• the first is to use backticks, ie the severe accent (`).

VAR=`echo "$VAR" | sed r -n "s/[0-9]+/X/p"`

• the second would be to use the syntax $(comando)

VAR=$(echo "$VAR" | sed r -n "s/[0-9]+/X/p")

The second case is easier to read and allows you to nestle commands more easily, but that’s up to you. If you want more information, the name of this is command override.

To keep the formatting with the spaces between the numbers and the text, it is necessary to leave its variable between ". Therefore, the correct code would be

VAR="oi                                 200          20   10"
VAR=$(echo "$VAR" | sed -r -n "s/[0-9]+/X/p")
echo "$VAR"