Replace specific letter in a file by other letter

Shell Programming and Scripting
1

Good afternoon all,
I want to ask how to change some letter in my file with other letter in spesific line

eg.
data.txt

1
1
1
0
0
0
0

for example i want to change the 4th line with character 1.
How could I do it by SED or AWK.

I have tried to run this code but actually did not modify the data.txt file and just print the result to screen.

sed -e "4s/0/1/" data.txt
2

That's how it works. Redirect the output to a temp file and then, mv the temp file to data.txt, overwriting it.

3

Or, use ed instead of sed :

ed data.txt <<-EOF
	4s/0/1/
	w
	q
EOF

or:

printf '%s\n' '4s/0/1' w q | ed data.txt
4

With GNU sed and BSD sed, there is the -i option for in-place editing, but there the recommend option is to have it automatically create a backup file as well..