How would you replace the n character in a file with some xyz?

sed 's/n/xyz/g' filename > new_filename

vi file name

then go to command mode

%s/n/xyz/g

tail -1 sample.txt | sed 's/.$/xyz/'Check this

using perl we can do.

perl -p -i -e "s/n/abc/g" file_name

We can replace n characters by using the following command:
1,$s/./xyz/g
where 1 shows that the search string will start searching patterns from first line of the file.
           '.' for any character.
            g for global replacement.

FOLLOWING IS THE ANSWER FOR REPLACING RANGE OF CHARACTERS IN A LINE OF FILE.  HERE 5TH TO 10TH CHARACTERS IN THE FILE text.txt ARE REPLACED BY "XYZ"

cut -c5-10 text.txt | sed 's/^.*$/XYZ/g'

search for the character n in filename and replace it with xyz.
sed 's/n/xyz/g' filename

sed  -i  's///g'  

sed -i option will directly changed in the fine. no need to redirect the output and create the another file. Here "g" for globe change.

Shambhu

After opening the file in vi editor:
come to command mode (press Esc), then type the below command

:s 1,$ s/n/xyz/g enter

All the sed replacements are by default global. It's in the vi editor that you have to specifically give "g" for global replacement.

:1,$s/n/xyz/g

:%s/n/xyz/g
Also be used in VI editer, % means globally

Also can be done with :g/n/s//xyz/g

cat cc | sed s/n/xyz/g