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Need help with sed and regexp

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# 1  
Old 08-23-2012
Question Need help with sed and regexp
Hi everyone, I would really appreciate any help I could get on the following topic.
I am not very familiar with reg expressions nor with sed, I just know the basic uses. What I am trying to do is the following: I have a huge text file where I would like to replace all occurnces of a certain pattern with another one. Here an example:

Code:
 "name1" = "12;15";
  "name5" = "7";
  "abc1" = "3";
  "5" = "";
  "-7" = "";
  "hgf" = "12;15";
  "e1" = "8";
  "-5" = "";

Should change to:

Code:
  "name1" = "12;15";
  "name5" = "7";
  "abc1" = "3;5;-7";
  "hgf" = "12;15";
  "e1" = "8;-5";

The rule is: any assign statement to a variable starting with a letter ( like "name1" ) is preserved, while any assignment to a numerical variable ( like "1" or "-1" should be appended to the previous line.

I couldnt get it to work because of the condition is across more than one line. I know I am supposed to use the N instruction but dunno how. Any help how to do the above with sed or any other way is cery appreciated.

Thanks.
# 2  
Old 08-23-2012
I think it's easier to code, read, maintain in awk:

Code:
awk -F = '
    match( $1, /"(-*[0-9]+)"/, hit ) {
        gsub( "\";", ";" hit[1] "\";", p );
        next;
    }
    {
        if( p )
            print p;
        p = $0;
    }

    END {
        if( p )
            print p;
    }
' input-file >output-file

These 2 Users Gave Thanks to agama For This Post:
Boxtuna Chubler_XL
# 3  
Old 08-24-2012
Pls help me out: which awk version supports match(s, r, X)? mawk does not. And what is the resulting action? Couldn't find in this forum's man pages.
# 4  
Old 08-24-2012
From man page(s) for gawk:
Code:
       match(s, r [, a])       Return the position in s where the regular expression r occurs, or 0 if r is not present, and set
                               the  values  of RSTART and RLENGTH.  Note that the argument order is the same as for the ~ opera‐
                               tor: str ~ re.  If array a is provided, a is cleared and then elements 1  through  n  are  filled
                               with  the  portions of s that match the corresponding parenthesized subexpression in r.  The 0'th
                               element of a contains the portion of s matched by the entire regular  expression  r.   Subscripts
                               a[n,  "start"],  and  a[n,  "length"] provide the starting index in the string and length respec‐
                               tively, of each matching substring.

# 5  
Old 08-24-2012
Ah, gawk. Got it, thank you!
# 6  
Old 08-24-2012
agama, thanks a lot! Your awk example works like a charm.
# 7  
Old 08-25-2012
Note that if you're on a system that doesn't have gawk and awk's match() function only takes two arguments (such as on OS X), the following should also work:
Code:
awk -F = '$1 ~ /"(-*[0-9]+)"/ {
        split($1, f, "\"")
        sub( "\";", ";" f[2] "\";", p )
        next
}
        { if(p) print p
        p = $0
}
END { if(p) print p
}' input_file > output_file

This User Gave Thanks to Don Cragun For This Post:
Boxtuna
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