view non-printable characters
we can use cat command and od commands to see the non-printable characters.
Let me explain how to create some non printable characters.
1) open the console and type the below.
2) echo “Hello <ctrl + v> <ctrl +m> World” > myfile.txt
Note :– <ctrl+v> means press control key and v in the keyboard.
3) Once the file is created, use cat command to view the file contents
1 2 3 4 | $ echo "Hello ^M World" > myfile.txt $ cat myfile.txt World |
4)As you notice, Hello word is disappeared.
5) use the -v option in the cat command.
1 2 | $ cat -v myfile.txt Hello ^M World |
6) Now you can see the word “Hello” but after that you can see some special character (^M) which is not printed while using the cat command
7) now we can use od command to see the special characters.
1 2 3 | $ od -c myfile.txt 0000000 H e l l o \r W o r l d \n 0000016 |
You can clearly see there is come special character \r present between the Hello and World.
Control-M is carriage return without linefeed.
How to remove the special characters ?
In this case, we can remove \r (which is clearly found by od -c command )
1 2 3 4 5 6 7 | $ cat -v myfile.txt Hello ^M World $ sed -i 's/\r//' myfile.txt $ cat -v myfile.txt Hello World |
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