Remove special characters from string

chebarbudo · #1 (**permalink**) 12-04-2008

Hi there,
I'd like to write a script that removes any set of character from any string. The first argument would be the string, the second argument would be the characters to remove. For example:

Code:

$ myscript "My name's Santiago. What's yours?" "atu"
My nme's Snigo. Wh's yors?

I wrote the following code:

Code:

$ cat myscript
ans=$1
for (( i=0; i<${#2}; i++ )); do
    ans=${ans//${2:$i:1}/}
done
echo "$ans"

But it doesn't work with the following special characters: #%*?\
Is there any simplier way to do that?
How can I make it work with all the characters?

Thanks in advance
Santiago

Wolfclaw · #2 (**permalink**) 12-04-2008

Try passing the special characters with a \ in front.
On the other hand why not simply use regular expressions with sed or perl etc. ?

Franklin52 · #3 (**permalink**) 12-04-2008

Or simply with tr. Check the -d option in the man page.

Regards

chebarbudo · #4 (**permalink**) 12-04-2008

Quote:

Originally Posted by Wolfclaw

Try passing the special characters with a \ in front.
On the other hand why not simply use regular expressions with sed or perl etc. ?

That's exactly what I was asking! I'm sure there's a simpler way of doing that... But how?
I cannot pass the special characters with a backslash because my script reads the second argument character by character. So if $2 is "\#", the script will first try to replace \ (and it fails) then try to replace # (and it fails too).
Any other idea?

Wolfclaw · #5 (**permalink**) 12-04-2008

for some reason its working with single quotes in the command line arguments. I dont know why this is though *shrugs*

radoulov · #6 (**permalink**) 12-04-2008

And what's wrong with Franklin52's solution?

This is with bash:

Code:

$ ./s "My name's Santiago. What's yours?" 'atu'
My nme's Snigo. Wh's yors?
$ ./s "My# name%'s ?Santiago.\ What/'s yours?" '#%?/\'
My name's Santiago. What's yours
$ cat s
#! /bin/bash

tr 2>&- -d "$2"<<<"$1"

chebarbudo · #7 (**permalink**) 12-04-2008

Quote:

Originally Posted by Franklin52

Or simply with tr. Check the -d option in the man page.

Great! The only character that do not work is backslah but here my new solution:

Code:

~$ cat myscript
echo "$1" | tr -d "${2//\\/\\\\}"
~$ myscript 'weird string !"#$%&'\''()*+,-./:;<=>?@[\]^_`{|}~' ' !"#$%&'\''()*+,-./:;<=>?@[\]^_`{|}~'
            <---------------------- $1 ----------------------> <---------------- $2 ---------------->
weirdstring
~$

Thanks a lot

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