how do I store the output of a cut -c command into a variable in shell script

Question

I have a file name like

Incoming_file_180420053826.csv

where 180420 represents the date and 053826 represents time.
I have used echo $( cut -c 15-20 $filename ) to retrieve the date, but I'm unable to store that output date in a variable.

Answer 1

Try

my_var="$( echo  $filename | cut -c 15-20 )"

Demo:

$filename=Incoming_file_180420053826.csv 
$my_var="$( echo  $filename | cut -c 15-20 )"
$echo $my_var 
180420
$

Answer 2

filename=test.txt
aa=$( cut -c 1-6 $filename )
echo $aa

180420 180421 180422 180423 180424 180425

But I think you maybe just need first line, maybe this is what you need.

bb=$(head -1 $file|cut -c 1-6)
echo $bb

180420