how to remove “^@” from text files in unix?

I am trying to remove “^@” from multiple text files using Unix platform. I have already found this solution, but it does not work for my case. I also used sed -i -e 's/^@//g' testfile.txt and dos2unix testfile.txt. sample data are put here.

Any suggestion would be appreciated.

Answer

The ^@ that you’re seeing isn’t a literal string. It’s an escape code for a NUL (character value 0). If you want to remove them all:

tr -d '' <test.txt >newfile.txt

To help diagnose this sort of thing, the od (octal dump) utility is handy. I ran this on the test file you linked, to confirm that they were NULs:

$ od -c test.txt | head
0000000     A     i     r     Q     u     a     l     i
0000020     t     y     S     t     a     t     i     o
0000040     n     E     o     I     C     o     d     e
0000060    n     D     E     H     E     0     4     4
*
0000400    n     D     E     H         E     0     4  
0000420   4    n     D     E     H     E     0     4  
*
0422160   4    n  n
0422164