capture first n characters of every line

Question

I'm having troubles capturing the first 6 characters of every line. Supposing I have the following lines inside text.txt:

this is a sentence
1234567890
string

I would like to get the first 10 chars:

this i
123456
string

I've tried running grep -Eo "^[a-zA-Z0-9]*{6}" text.txt

But grep recycles the regex at every 6th position instead of starting at the next new line. it ends up returning:

this i
s a se
ntence
123456
7890..

what am I doing wrong here?

Answer 1

Why to use grep, you can use simple cut command:

cut -c1-6 file

OR else this more complex sed will also work:

sed 's/^\(.\{6\}\).*$/\1/' file

Answer 2

Use following command:

grep -Eo "^.{6}" text.txt

Above command omit lines with <6 characters. To include such lines, use following command:

grep -Eo "^.{1,6}" text.txt