sed multiline substitution if a condition holds Post: 302564701

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Top Forums Shell Programming and Scripting sed multiline substitution if a condition holds Post 302564701 by CarloM on Friday 14th of October 2011 11:35:44 AM

10-14-2011

Registered User

I'm not sure I understand your conditions. Is the ELSE ever going to be executed except at the start of the file (i.e. before we encounter the first varx assignment)?

Put another way, what output would you expect from:

Code:

dummy3 = 7; vary = 'option1'; dummy4 = 8;
dummy1 = 5; varx = 'false'; dummy2 = 6;
dummy3 = 7; vary = 'option1'; dummy4 = 8;
dummy3 = 7; vary = 'option1'; dummy4 = 8;
dummy1 = 5; varx = 'true'; dummy2 = 6;
dummy3 = 7; vary = 'option1'; dummy4 = 8;

(with whatever in-between the varx/vary lines)

EDIT: A possible (and rather messy Smilie

) awk solution:

Code:

#  cat xx.awk
BEGIN {
        FS=";";
        xval=-1;
        if (NEWVAL1=="") NEWVAL1="'optionA'";
        if (NEWVAL2=="") NEWVAL2="'optionB'";
}
$2 ~ /varx *= *'false'/ {
        xval=0;
        print;
}
$2 ~ /varx *= *'true'/ {
        xval=1;
        print;
}
$2 ~ /vary *= */ {
        if (xval==1) {
                printf ("%s; vary = %s", $1, NEWVAL2);
                x=3;
        }
        else if (xval==0) {
                printf ("%s; vary = %s", $1, NEWVAL1);
                x=3;
        }
        else {
                printf ("%s", $1);
                x=2;
        }
        for (i=x;i<=NF;i++) {
                printf ("; %s", $i);
        }
        printf ("\n");
}
$2 !~ /var[xy] *= */ {
        print;
}

Code:

# cat xx.txt
dummy3 = 7; vary= 'option1'; dummy4 = 8;
% whatever
dummy1 = 5; varx = 'false'; dummy2 = 6;
% whatever
% whatever
dummy3 = 7; vary =  'option1'; dummy4 = 8;
dummy3 = 7; vary='option1'; dummy4 = 8;
% whatever
dummy1 = 5; varx  = 'true'; dummy2 = 6;
% whatever
% whatever
dummy3 = 7; vary ='option1'; dummy4 = 8;
% whatever

Code:

# awk -f xx.awk xx.txt
dummy3 = 7;  vary= 'option1';  dummy4 = 8;
% whatever
dummy1 = 5; varx = 'false'; dummy2 = 6;
% whatever
% whatever
dummy3 = 7; vary = 'optionA';  dummy4 = 8;
dummy3 = 7; vary = 'optionA';  dummy4 = 8;
% whatever
dummy1 = 5; varx  = 'true'; dummy2 = 6;
% whatever
% whatever
dummy3 = 7; vary = 'optionB';  dummy4 = 8;
% whatever

Last edited by CarloM; 10-14-2011 at 01:04 PM..

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