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Need help with a sed script

 
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# 1  
Old 02-28-2012
Need help with a sed script
Hello,
I'm trying to write a sed script for this.
I have to delete the '\i' and '\b', except when it is between \* \*
Here is an example:

Before sed script:
Code:
I \* hope \bthat \b I \* \iwill \i find \*\bthe \b answer.\*

After sed script:
Code:
I hope \bthat \b I will  find \bthe \b answer.

What is the best way to do it?
Do I have to use pattern and hold space?
I'm looking for a general solution, that will work on every text.
Last edited by ikke008; 02-28-2012 at 03:21 PM..
# 2  
Old 02-28-2012
Not homework, I hope!

Not really a good sed problem. You can do it, but it seems messy. Only by counting can you tell that a \* is opening or closing a protected zone. If you split the line zones into lines you mark to support reassembly, like with a \ just before added end of line, then you can work on the safe lines and avoid the others, then reassemble. So, might be three sed's in a row! What do \*, \b and \i represent? 'i' does not need escape. Sometimes \b is backspace ^H. Are the \ literal in the input file?
# 3  
Old 02-28-2012
Not homework, it's from a specific markup language.
How can I do it by counting? Do I have to split the line then?
I thought when I use '\n' in a replacement, sed would see it as a character, not as a new line?
\* safe zone that cannot be changed /* can be changed /*can not be changed ....
# 4  
Old 02-28-2012
Hi ikke008,

Here it is. I struggled too much to get it. It must be homework because it has no sense to use sed with more suitable tools for the task. It may be wrong because it is a mess, but try:
Code:
$ cat infile
I \* hope \bthat \b I \* \iwill \i find \*\bthe \b answer.\*
$ cat script.sed
## Substitute '\*' with '\n'.
s/\\\*/\n/g

## If there is a odd number of '\*' or the string doesn't end with '\*', I 
## will append some at the end. There is no danger, but it will be used to
## avoid an infinite loop.
## 1.- Save content to 'hold space'.
## 2.- Remove all characters except '\n'.
## 3.- Remove one of them because next command will add another one.
## 4.- Put content in 'pattern space' to begin working with it.
## So, if in original string there were 3 '\*', now there will be 6. ˇFine!
h
s/[^\n]//g
s/\n//
H
g

## Label 'a'.
:a

## Save content to 'hold space'.
h

## Remove from first '\n' until end of line.
s/\(\n\).*$/\1/

## Remove all '\i' and '\b'.
s/\\b\|\\i//g

## Change '\n' with original '\*'.
s/\n//

## Append content to print as final output to 'hold space'.
H

## Recover rest of line from 'hold space'.
g

## Remove content printed just before.
s/[^\n]*//

## Save content to 'hold space'.
h

## Get first content between '\n'.
s/\(\n[^\n]*\n\).*$/\1/

## Remove all '\n' found.
s/\n//g

## Append content to print as final output to 'hold space'.
H

## Recover rest of line from 'hold space'.
g

## Remove content printed just before.
s/\n[^\n]*\n//

/^\n/ { 
    s/\n//g
    p   
    q   
}

ba
$ sed -nf script.sed infile
I  hope \bthat \b I  will  find \bthe \b answer.

Regards,
Birei
# 5  
Old 03-01-2012
Hello friends ,

I need help with passing array variabls in sed command on unix. I tried below command and it picks up the value from array but something is wrong as it throws garbled sed. Please help me fixing it.

sed -n "/(${tags[2]}\)/,/\(${tags[1]})\/p" patch_list.txt

Out put on unix is .....

sed: command garbled: /\(FW_12_10\)/,/\(FW_R12_06)\/p
 
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