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Hi, I am newbie in unix shell programming.
Can someone tell how to check that a variable that have a certain text?

    e.g.
    M=File.ddv
    if [ ${M} = "*.ddv" ]; then
        echo This is ddv file
    fi

   Obviously above does not work.
   How can do it with sed...?? [A-Za-z0-9]*.ddv ??

Thanks, AT

There is probably a number of different tools and ways to accomplish this task
in a simpler manner, but if you want to do it with sed specifically do this.
for a good tutorial on sed to explain what I'm doing...goto:
http://www-106.ibm.com/developerworks/linux/library/l-sed2.html?dwzon...

M=File.ddv
FILE_EXTENSION=$(echo $M | sed -e s/^.*[.]//g )

if [ ${FILE_EXTENSION} = "ddv" ]; then
echo This is ddv file
fi

Quote:

>Hi, I am newbie in unix shell programming.
>Can someone tell how to check that a variable that have a certain text?

>    e.g.
>    M=File.ddv
>    if [ ${M} = "*.ddv" ]; then
>        echo This is ddv file
>    fi

>   Obviously above does not work.
>   How can do it with sed...?? [A-Za-z0-9]*.ddv ??

>Thanks, AT

Use 2 [[]] instead of 1 [].  Otherwise you are getting filename
expansion out of the *.  And then take the * outside of the
""'s so it isn't considered a literal "*".

    M=File.ddv
    if [[ ${M} = *".ddv" ]]; then
        echo This is ddv file
    fi

 - Matt
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  IBM High Speed Interconnect - Fibre Channel I/O Dev/Test/Support
   << Comments, views, and opinions are mine alone, not IBM's. >>

Try (in Posix type shells):
    if [[ $M = *.ddv ]]; then

Quote:>    Obviously above does not work.
>    How can do it with sed...?? [A-Za-z0-9]*.ddv ??

You could use sed, but expr would be better:
    if [ `expr $M : ".*\.ddv` = 0 ]; then
        echo This is ddv file
    fi

(You could use -eq instead of = to emphasise you are dealing with numbers
but the above should work)
regards,
Ben

I slipped up - the above should be:
    if [ `expr $M : ".*\.ddv"` != 0 ]; then
        echo This is a ddv file
    fi

Quote:>Hi, I am newbie in unix shell programming.
>Can someone tell how to check that a variable that have a certain text?

>    e.g.
>    M=File.ddv
>    if [ ${M} = "*.ddv" ]; then
>        echo This is ddv file
>    fi

>   Obviously above does not work.
>   How can do it with sed...?? [A-Za-z0-9]*.ddv ??

This is definently not a job for 'sed' (however
see below), use the shell built-in 'case';

case "$M" in
*.ddv) echo this is a ddv file;;
esac

There is documentation for 'case' on the shell
man-page (man sh).

If you really wanted to use 'sed' to match these strings
you would have to put a backslash before the period
(because otherwise a period will match any character)
also you would have to anchor it with ^ and $ to make
sure it matched only the whole string;

/^[A-Za-z0-9]*\.ddv$/

But making 'sed' somehow to tell the shell to act
one way or another because it matched the string
would just get plain ugly...

print the string if it matches (like grep);

echo $M |sed '/^[A-Za-z0-9]*\.ddv$/!d'

count the number of lines;

echo $M |sed '/^[A-Za-z0-9]*\.ddv$/!d' |wc -l

if the number of lines is 1 then its okay;

if [ `echo $M |sed '/^[A-Za-z0-9]*\.ddv$/!d' |wc -l` -eq 1 ]
then
  echo its a ddv file
fi

see what I mean !? ;) it could be done by instead getting
'sed' to print 'true' or 'false' and using that as a command
(and maybe could be made a bit shorter) but its not really
the tool for the job when you have 'case' (at least here,
where you only really need a shell pattern and not a regular
expression)

'grep' is (slightly) better here because it returns 'true' if
it finds a match and 'false' if it doesn't so you can
do away with more than half of the above but have to
add a >/dev/null to stop it printing stuff out;

if echo "$M" |grep '^[A-Za-z0-9]*\.ddv$' >/dev/null
then
  echo its a ddv file
fi

byefrom,
: ${L} # http://lf.8k.com:80

Quote:

>Thanks, AT

at schrieb:

Quote:> Hi, I am newbie in unix shell programming.
> Can someone tell how to check that a variable that have a certain text?

>     e.g.
>     M=File.ddv
>     if [ ${M} = "*.ddv" ]; then
>         echo This is ddv file
>     fi

>    Obviously above does not work.
>    How can do it with sed...?? [A-Za-z0-9]*.ddv ??

> Thanks, AT

In Posix- and Korn-Shell use the new  [[ ... ]]  (test-command)

[[  ${M} =  *.ddv  ]]   &&   echo This is ddv file

btd.heck.vcf < 1K Download

case $M in
   *.ddv) echo This is ddv file ;;
   *) echo This is not ddv ;;
esac

Quote:> >    e.g.
> >    M=File.ddv
> >    if [ ${M} = "*.ddv" ]; then
> >        echo This is ddv file
> >    fi

  Maybe this would do what you lookin for?

  M="File.ddv"
  if [ "${M%.ddv}" != "${M}" ]
  then
   echo "This is ddv file"
  fi

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                       George Athanassopoulos                          
=====================================================================

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Hi,
    I try your suggestion for a size.
    It didn't work.
    But FILE_EXTENSION=echo $M | sed -e 's/^.*[.]//g'
    is ok.

    I have not use $(...) b4. What is about?
    /andrew

Sorry, I try this it doesn't work.
    Error message bad subsitution.

    /andrew

For a possibly shorter comparison, just look at the extension:

M="/users/myhome/mydir/work/file.ddv"
if [ "${M##*.}" = "ddv" ] ; then
    echo "This is a ddv file"
fi

"##*." removes the longest string from the front of the variable's contents
that ends
with a dot.  In this case, it removes "/users/myhome/mydir/work/file.",
leaving
"ddv".

Pope,
that is not quite correct because if the file is called ddv then the case
is screwed. If you M="ddv" then your script works incorrectly reporting
that "ddv" is a ddv file (meaning it has got a .ddv extension).
While:
#!/bin/bash
 M="ddv"
   if [ "${M%.ddv}" != "${M}" ]
   then
     echo "This is ddv file"
   fi

works just fine.

--
=====================================================================
                       George Athanassopoulos                          
=====================================================================

 WWW   : http://www.egnatia.ee.auth.gr  http://www.real.macedonia.gr
=====================================================================
 PGP Key: http://egnatia.ee.auth.gr/~athanas/pgp_public_key.asc  
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