Trying to remove non-printable charaters(junk values) from a UNIX file

Question

I am trying to remove non-printable character (for e.g. ^@) from records in my file. Since the volume to records is too big in the file using cat is not an opti

Answer 1

Remove all control characters first:

tr -dc '\007-\011\012-\015\040-\376' < file > newfile

Then try your string:

sed -i 's/[^@a-zA-Z 0-9`~!@#$%^&*()_+\[\]\\{}|;'\'':",.\/<>?]//g' newfile

I believe that what you see ^@ is in fact a zero value \0.
The tr filter from above will remove those as well.