topic Re: control M characters in Operating System - Linux

control M characters

Rinky — Thu, 31 May 2007 05:55:51 GMT

Hi,
I wanna check if a file contains control M [^M]
characters in it.
Not a perl script, but a shell script solution.
Can I check for it

Re: control M characters

Dennis Handly — Thu, 31 May 2007 06:09:51 GMT

If you want to just convert them, you can use dos2ux(1).

Otherwise you can use grep but you'll have problems getting a control M into the shell.

I was able to use control V, then control M in vi to get:
$ fgrep -q ^M file

Re: control M characters

Yogeeraj_1 — Thu, 31 May 2007 06:35:47 GMT

hi

try:
find . -type f |xargs grep -l ^M

Where the ^M character should be typed as:
ctrl+v ctrl+m

hope this helps!

kind regards
yogeeraj

Re: control M characters

Rinky — Thu, 31 May 2007 06:53:10 GMT

fgrep -q ^M file
dint work..
I have attached the file.
You can test this file

Re: control M characters

Dennis Handly — Thu, 31 May 2007 07:02:50 GMT

>fgrep -q ^M file
dint work.

Works fine for me using a real shell. As I said, you have to create a script with control M. You can't enter it directly to the shell.

Re: control M characters

Dennis Handly — Thu, 31 May 2007 07:04:46 GMT

Here is my script.

Re: control M characters

James R. Ferguson — Thu, 31 May 2007 08:00:05 GMT

Hi Rinky:

What's (?) so hard with:

# perl -ne 'print if /\015/' file

THe \015 is the octal code for a Carriage-Return which is graphically seens as ^M. The Perl snippet reads every line of a 'file' passed printing any line that has a carriage-return in it.

Regards!

...JRF...

Re: control M characters

OldSchool — Thu, 31 May 2007 09:18:49 GMT

...or you can stick the ^M in a "pattern file" and use it. for example, file "P1" contains the Ctrl-M, then you can do:

grep -f P1

or for all Control characters, try

grep [:ctrl:]

Re: control M characters

Sandman! — Thu, 31 May 2007 09:33:40 GMT

Simplest would be to grep for the Ctrl-M character which is inserted into the cmd line by holding down the "Ctrl", "V" and "M" keys simultaneously on your keyboard i.e.

# grep -q ^M infile && echo "Ctrl M chars found" || echo "No Ctrl M chars found"

Re: control M characters

OldSchool — Thu, 31 May 2007 09:50:02 GMT

FYI:

Sandman, your solution occurred to me also, but when i tried it in ksh on 11.0, entering that key sequence generated a Ctrl-J on the command line. Suspect its an issue w/ "set -o vi" / .exrc / .kshrc, but didn't check further...just proceeded on in a different direction

Re: control M characters

Sandman! — Thu, 31 May 2007 10:46:36 GMT

You're right OldSchool I am unable to duplicate the command line I created under the sh-posix(1) shell. Hmmm...needs to be looked into.

Re: control M characters

A. Clay Stephenson — Thu, 31 May 2007 10:59:01 GMT

Here's a sneaky way to do it leveraging echo.

If testing a shell variable then:

echo "${MYVAR}" | grep -q $(echo "\r\c")
STAT=${?}
if [[ ${STAT} -eq 0 ]]
then
echo "CR Found"
fi

If testing a file:

grep -q $(echo "\r\c") infile
STAT=${?}
if [[ ${STAT} -eq 0 ]]
then
echo "CR Found"
fi

Re: control M characters

Dennis Handly — Thu, 31 May 2007 14:36:08 GMT

>Sandman: I am unable to duplicate the command line I created

I kept saying that. But vi allows ^M.

Re: control M characters

Arturo Galbiati — Fri, 01 Jun 2007 03:18:41 GMT

Hi,
grep [\015] file

it's ok on my Hp-UX 11i

HTH,
Art

Re: control M characters

Dennis Handly — Sat, 02 Jun 2007 02:39:54 GMT

>Art: grep [\015] file

I almost took you at your word since I didn't check this. (I forgot what Ronnie said. ;-)
But now I did and this does not work in a real shell. What shell did you use?

A similar (but quoted) syntax works in tr(1): "[\015]"

Re: control M characters

freddy_21 — Sun, 03 Jun 2007 20:52:27 GMT

try to run
#dos2ux test1 > test2

your ^M will be remove at file test2.

thanks
freddy

Re: control M characters

Rinky — Tue, 05 Jun 2007 03:32:26 GMT

grep -q $(echo "\r\c") infile
STAT=${?}
if [[ ${STAT} -eq 0 ]]
then
echo "CR Found"
fi

worked fine..
thanks..

Re: control M characters

Rinky — Tue, 05 Jun 2007 03:33:23 GMT

WOW!!
dos2ux test1 > test2
perfect command..
Thanks a lotttttt...

Re: control M characters

Hein van den Heuvel — Tue, 05 Jun 2007 06:28:15 GMT

Well duh!
Just like you were informed in the very first reply a week ago!

Cheers,
Hein.

Re: control M characters

Dennis Handly — Tue, 05 Jun 2007 06:37:58 GMT

>Hein: Just like you were informed in the very first reply a week ago!

Exactly.

Other than Clay's echo trick, OldSchool's file of CR and JRF's perl script, nothing was added since my first reply.
(And I only got 4 points. Though Rinky can add some more. ;-)