One of my input file had some control characters (^B i.e. hex \x02)
On my Ubuntu 8.04.3 and GNU grep version of
$ grep --version
GNU grep 2.5.3
I can grep for any control characters like this:
$ grep '[[:cntrl:]]' /tmp/file.txt
$ grep '[[:cntrl:]]' /tmp/file.txt | less
Also if you know what to grep for, say in above example the control character is ^B (hex \x02); then you can directly grep for it like this
$ grep ^B /tmp/file.txt
* ^B to be typed as ctrl V and ctrl B
And to match any non printable characters, here is another way using grep
$ grep '[^[:print:]]' /tmp/file.txt
To display non printable characters, here is a way using GNU cat command (My cat version : cat GNU coreutils 6.10)
$ cat -v -e -t /tmp/s
Output:
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8 comments:
Your blog is helpful to the code geek people
Nasif
I find it easier to use Perl regexps and the hex value...
grep -P "\x02" myfile.txt
hello,
I am looking to include control characters in a script. Is there a way for a shell to translate asci into the control characters to then be piped in netcat?
Hello,
I am looking to include control character in a bash script. It there any way for bash to translate asci into the special control characters?
Cheers
Dan
@djhayman, something like:
printf "\x01\n" | less
which is ^A (control A)
thanks for the question.
Hello,
Thanks very much for your reply Jadu. I am having a bit of trouble formatting the command.
The command is
0x02PON0x030x0d
Can you help?
Cheers
Dan
@djhayman, could you please explain your last query again with an example, I would definitely help you here.
Do you mean something like ?
printf "0\x02PON0\x030\x0d" | less
Which is:
0^BPON0^C0
Hi Jadu,
Sorry for such a late reply.
Basically, we have some TVs on a network which can be controlled over the LAN. We have some software that does this but I am exploring making a piece of software dedicated to control them.
I have been able to control them by inputting 0x02PON0x03 into this website http://chxo.com/scripts/hex2string.php then taking the special characters and saving them in a text file. Next I would pipe the text file into a net cat command.
I would like to create an application that has greater flexibilty rather than requring a pre made text file for each command.
I hope I have been clear.
Thanks,
Dan
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