Using Raku (formerly known as Perl_6)
[Adds extra blank line at end]:
raku -ne 'my ($L1,$L2,$L3,$L4) = (get) xx 4; .put for $L3, $L1, $L2, $_, ($L4 // "");'
#OR
raku -e 'my @a.=push($_) if .chars for lines; put($_ ~ "\n") for @a.rotor(4)>>.[3,1,2,0]>>.join("\n");'
[Doesn't add extra blank line at end]:
raku -ne 'my ($L1,$L2,$L3,$L4) = (get) xx 4; .put for $L3, $L1, $L2, $_; $L4.defined ?? $L4.put !! next;'
#OR
raku -e 'my @a.=push($_) if .chars for lines; .put for @a.rotor(4)>>.[3,1,2,0]>>.join("\n").join("\n\n");'
First and third examples are similar to Perl5 code posted by @ForeverCuber, and bears a vague resemblance to awk code posted by @RudiC. First/third examples use -ne commandline flags. Second/fourth examples push lines onto an @-sigiled array.
For the first example the -ne commandline flags means the first line loads into $_, Raku's topic variable. Raku is instructed to get 4 successive lines, which load into each of ($L1,$L2,$L3,$L4). The Record Separator is represented by $L4 which, when undefined (at end), is handled using Raku's // defined-OR operator. Thus "" blank string is output if left-side of // evaluates to undefined. Printing is simplified without any joins and by the use of put only.
Second example pushes lines onto an array, @a. Blank lines are skipped via the conditional if .chars. Array elements are rotored together (grouped into 4-element sublists/records), reordered with [3,1,2,0] indexing, and joined with one call to join("\n"). Printing of records is simplified by use of put($_ ~ "\n"), which demonstrates that string concatenation is accomplished via ~ tilde in Raku.
Third example is similar to first example in that it uses -ne commandline flags, and again, no joins are used. However undefined last line is handled better by Raku's "Test ?? True !! False" ternary operator (i.e. $L4.defined ?? $L4.put !! next;). Thus no extra blank line is added at the end. Note: print "" could be used here, in place of next.
Fourth example is similar to second example, except output is built up by two successive calls to join, which recreates the original record spacing (and no extra blank line is added at the end). The first >>.join("\n") call maps into the rotored record to join the 4 lines into a single array element. The second .join("\n\n") takes the resultant 5 array elements (records) and joins them with a blank space in-between each, recreating the input but with the desired line-ordering.
Sample Input (lines have been numbered):
1 DelegatedAdmin: cn=fb6190f7-4a33-4502-a2d5-dce8dc434570,ou=Named,ou=Identities,ou=Active,ou=Vault<br />
2 changetype: modify<br />
3 delete: DelegatedAdmin<br />
4 dn: cn=311999,ou=Entities,ou=Active,ou=Vault<br />
5 DelegatedAdmin: cn=fb6190f7-4a33-4502-a2d5-dce8dc434570,ou=Named,ou=Identities,ou=Active,ou=Vault<br />
6 changetype: modify<br />
7 delete: DelegatedAdmin<br />
8 dn: cn=948089,ou=Entities,ou=Active,ou=Vault<br />
9 DelegatedAdmin: cn=fb6190f7-4a33-4502-a2d5-dce8dc434570,ou=Named,ou=Identities,ou=Active,ou=Vault<br />
10 changetype: modify<br />
11 delete: DelegatedAdmin<br />
12 dn: cn=947458,ou=Entities,ou=Active,ou=Vault<br />
13 DelegatedAdmin: cn=9776c3f8-f2ee-4b6c-a9a9-32d87b45f7c5,ou=Named,ou=Identities,ou=Active,ou=Vault<br />
14 changetype: modify<br />
15 delete: DelegatedAdmin<br />
16 dn: cn=10717,ou=Entities,ou=Active,ou=Vault<br />
17 DelegatedAdmin: cn=e0a838f0-3d53-42e8-8dad-bd1d774381de,ou=Named,ou=Identities,ou=Active,ou=Vault<br />
18 changetype: modify<br />
19 delete: DelegatedAdmin<br />
20 dn: cn=1500,ou=Entities,ou=Active,ou=Vault<br />
Sample Output:
4 dn: cn=311999,ou=Entities,ou=Active,ou=Vault<br />
2 changetype: modify<br />
3 delete: DelegatedAdmin<br />
1 DelegatedAdmin: cn=fb6190f7-4a33-4502-a2d5-dce8dc434570,ou=Named,ou=Identities,ou=Active,ou=Vault<br />
8 dn: cn=948089,ou=Entities,ou=Active,ou=Vault<br />
6 changetype: modify<br />
7 delete: DelegatedAdmin<br />
5 DelegatedAdmin: cn=fb6190f7-4a33-4502-a2d5-dce8dc434570,ou=Named,ou=Identities,ou=Active,ou=Vault<br />
12 dn: cn=947458,ou=Entities,ou=Active,ou=Vault<br />
10 changetype: modify<br />
11 delete: DelegatedAdmin<br />
9 DelegatedAdmin: cn=fb6190f7-4a33-4502-a2d5-dce8dc434570,ou=Named,ou=Identities,ou=Active,ou=Vault<br />
16 dn: cn=10717,ou=Entities,ou=Active,ou=Vault<br />
14 changetype: modify<br />
15 delete: DelegatedAdmin<br />
13 DelegatedAdmin: cn=9776c3f8-f2ee-4b6c-a9a9-32d87b45f7c5,ou=Named,ou=Identities,ou=Active,ou=Vault<br />
20 dn: cn=1500,ou=Entities,ou=Active,ou=Vault<br />
18 changetype: modify<br />
19 delete: DelegatedAdmin<br />
17 DelegatedAdmin: cn=e0a838f0-3d53-42e8-8dad-bd1d774381de,ou=Named,ou=Identities,ou=Active,ou=Vault<br />
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