PERL : Use of a variable in a tr

Shell Programming and Scripting
1

Hi,

I want to count the number of occurences of a character in a string variable ($str). The character is stored in a another variable ($sepchr). I am using tr as :

 
$count = ($str =~ tr/$sepchr//);

This did not work. I found in another thread about using eval. I used eval as :

 
$count = ($str =~ eval "tr/$sepchr//");

But this too did not work.

Please advise.

Thanks

2

I would use global matching for that:

# perl -le'
  $s = "ababbaa";
  $c = shift;
  $n = () = $s =~ /$c/g;
  print $n;
  ' a
4
# perl -le'
  $s = "ababbaa";
  $c = shift;
  $n = () = $s =~ /$c/g;
  print $n;
  ' b
3
3

wat does 015 mean in this command?

tr -d \\015 < file
4 
$ man ascii | grep 015
Reformatting page.  Please Wait... done
     010 BS   011 HT   012 NL   013 VT   014 NP   015 CR   016 SO   117 SI

CR - Carriage Return.

1 Like
5

You could use the s/// operator as well, at the expense of modifying the original string -

$
$
$ perl -le '$str="ababbaa"; $sepchr="a"; $count = $str =~ s/$sepchr//g; print $count'
4
$
$
$ perl -le '$str="ababbaa"; $sepchr="b"; $count = $str =~ s/$sepchr//g; print $count'
3
$
$

tyler_durden

1 Like
6

many thanks for the previous post....

i want to remove ^M(ctrl-v ctrl-m) from a file through script using sed command...can u suggest sumthin.....

---------- Post updated at 09:33 AM ---------- Previous update was at 09:32 AM ----------

many thanks for the previous post....

i want to remove ^M(ctrl-v ctrl-m) from a file through script using sed command in shell script...can u suggest sumthin.....

7 
sed 's/^M//g' yourfile > newfile
8

i tried it...its not working through script.....the output file still contains ^M

---------- Post updated at 12:41 PM ---------- Previous update was at 12:36 PM ----------

i tried in thru script...but its not working....

9

Could this help you ?

perl -i -pe 's/\r//g' inputfile
1 Like
10

i need it in shell script....:frowning:

11

Try:

sed 's/type <Ctrl-V><ENTER> here//g' yourfile > newfile
12

its not working....

---------- Post updated at 03:21 PM ---------- Previous update was at 03:20 PM ----------

testt.sh:

sed 's/^@//g' newfile > chk

13

It did not work because you typed:

^@

despite being told to type:

<Ctrl-V><Enter>

No wonder it did not work.

tyler_durden

Try "\r" alternatively; looks like it works with GNU sed -

$
$ # display the contents of file "f1"
$ cat f1
1
12
123
$
$ # check the octal dump of "f1" to see the "\r" characters
$ od -bc f1
0000000 061 015 012 061 062 015 012 061 062 063 015 012
          1  \r  \n   1   2  \r  \n   1   2   3  \r  \n
0000014
$
$ # the shell script to remove "\r" characters
$ cat f1.sh
sed 's/\r//g' f1 > f1.new
$
$ # run the shell script
$ . f1.sh
$
$ # check the new file now
$ cat f1.new
1
12
123
$
$ od -bc f1.new
0000000 061 012 061 062 012 061 062 063 012
          1  \n   1   2  \n   1   2   3  \n
0000011
$
$
1 Like
14

super....thanks.....