Sort a line and Insert sorted word(s) in a line

Shell Programming and Scripting
1

Hello,

I am looking to automate a task - which is updating an existing access control instruction of a server and making sure that the attributes defined in the instruction is in sorted order. The instructions will be of a specific syntax.

For example lets assume below listed is one of an existing instruction in a server. Attributes are the ones in between the (targetattr = "xx || yy")

In this existing instruction,

1) First, i want to sort the attributes defined in ascending order like

2) Then on the sorted instruction, I may want to add 1 or more strings like "gabcd" and "gbace" in between the existing strings (alphabetically ordered). So the expected final result must be something like below

Can someone help me to achieve this ?

Thanks

2

If your awk supports asort you could try something like:

awk FS='"' '{
   MYFS="||";
   newlist="";
   n=split($2,elements,MYFS);
   asort(elements);
   for (i=1;i<n;i++) {
      newlist=newlist elements MYFS;
   }
   newlist=newlist elements[n];
   $2=newlist;
   print;
}' inputfile

(although I haven't tested it...)

3

Hey ! Thanks for your reply. I couldn't get that piece working. how do i find if my awk supports asort. And can you please explain the code ?

4

awk FS='"' ' - invoke awk with double-quote as the field separator.
{ - for any line
MYFS="||"; newlist=""; n=split($2,elements,MYFS); - Split field 2 into an array, using '||' to identify separate elements (and n assignment should be on split, not asort)
asort(elements); - Sort the array
for (i=1;i<n;i++) { newlist=newlist elements MYFS; } - loop around the (ordered) array to create a new string, appending the current element and '||' every time
newlist=newlist elements[n]; - append the last element (should be n rather than i, or it will repeat the last-but-one)
$2=newlist; - overwrite the value of field 2 with the list we just created
print; - print the line

5

I believe that asort() is only available in gawk (GNU awk). Try executing

awk --version

which might give you the version. Assuming it's not gawk, then you could implement your own sort. Probably not as efficient as the built-in, but better than nothing. Example below using the original code from CarloM and adding a sort (bubble) function.

awk FS='"' '

# sort v1 into ascending order
# n = length(v1) rather than passing in the length isnt supported in all flavours of awk
function bubble( v1, n,         s, i, pass, swap )
{
    swap = 1;
    pass = 0;

    while( swap )
    {
        swap = 0;
        pass++;
        for( i = 0; i < n - pass; i++ )
        {
            if( v1 > v1[i+1] )
            {
                swap++;
                s = v1;
                v1 = v1[i+1];
                v1[i+1] = s;
            }
        }
    }
}

{
   MYFS="||";
   newlist="";
   n=split($2,elements,MYFS);
   bubble( elements, n );   for (i=1;i<n;i++) {
      newlist=newlist elements MYFS;
   }
   newlist=newlist elements[n];
   $2=newlist;
   print;
}' inputfile
6

agama / CarloM,

mine is NOT a gawk. so i tried running manual sorting code by copying it to a script. It throws out syntax errors while executing the script. i am not an shell expert and unable to fix the syntax errors of this code. did this code worked for you ? please help !

7

I cut/pasted the code from another post I made a while back on Unix.com while en route on a plane, so I didn't test it. There's a chance that I chopped something off, but after a quick peek at it again it looks OK to me. If you could post the errors, and your code, that might help determine what isn't working.

I'm again on a plane; I'm sure someone will see it and suggest changes/corrections.