UNIX for Advanced & Expert Users

It is the cat -v that makes ^@ ambiguous. If you want to change null bytes in a file to pipe symbols, use tr; not cat and sed:

Code:

tr '\0' '|' < raw_file.dat > parsed_raw_file.dat

But, of course, if your data files contain other null bytes (such as in numeric values stored as type int or float instead of in strings), you will need something that actually parses the format of your .dat files and only changes the null bytes that are field delimiters in your data to pipe symbols.

Hi,
The tr command is THE solution is this case : it can translate easily any character like NUL , which is \0 for unix.
See :
( od -c is just here to show where the NUL is )

Code:

$ od -c n.tmp
0000000   a   a   a   a   \  \0   b   b   b  \n
0000012

$ tr '\0' '|' < n.tmp > n.txt

$ od -c n.txt
0000000   a   a   a   a   \   |   b   b   b  \n
0000012

Hi,
You can just use tr to replace null chars with anything you want , e.g. |
See:

Code:

$ od -c 1.tmp
0000000   w   e       h   a   v   e       n   u   l   l      \0  \0  \0
0000020       c   h   a   r   s  \n
0000027

$ tr \\000 \| < 1.tmp
we have null ||| chars