Assign variable to cut -f field - awk

Question

Using cut, I want to know how to use it as:
awk -v id=3 -v RS= -F '::' '($1==id) {print $3}' jenny | a=1 ;cut -d$'\n' -f$a
I want to use it in a loop where i is replaced with, e.g., -f 1...3
Input
0::chkconfig --list autofs::
autofs 0:off 1:off 2:on 3:on 4:on 5:on 6:off
1::grep "^PROMPT=" /etc/sysconfig/init::
PROMPT=yes
2::rpm -q prelink::
prelink-0.4.0-2.el5
3::if [ -z "$(grep -l "hard core" /etc/security/limits.conf /etc/security/limits.d/*)" ]; then echo "empty"; else echo -e "$(grep -l "hard core" /etc/security/limits.conf /etc/security/limits.d/*)"; fi::
/etc/security/limits.conf
/etc/security/limits.d/test
4::sysctl fs.suid_dumpable::
fs.suid_dumpable = 0
5::stat /etc/motd::
File: `/etc/motd'
Size: 17 Blocks: 16 IO Block: 4096 regular file
Device: fd00h/64768d Inode: 10125343 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2019-04-09 07:56:19.000000000 +0500
Modify: 2019-03-30 19:22:13.000000000 +0500
Change: 2019-03-30 19:22:13.000000000 +0500
Expected Output
/etc/security/limits.conf
/etc/security/limits.d/test
As field 1 and field currently it's all coming in $3. I tried separating with newline in awk; it doesn't seem to catch.

Answer 1

To get your desired output from the given input, try:
$ awk '/^$/{f=0} f{print} /3::/{f=1}' file
/etc/security/limits.conf
/etc/security/limits.d/test
To get only one output line as selected with a variable i:
$ awk -v i=1 '/3::/{n=NR+i} n==NR' file
/etc/security/limits.conf
$ awk -v i=2 '/3::/{n=NR+i} n==NR' file
/etc/security/limits.d/test
The awk variable i can, of course, be set to the value of a shell variable i:
$ i=2
$ awk -v i="$i" '/3::/{n=NR+i} n==NR' file
/etc/security/limits.d/test
The stanza can also be selected from a variable:
$ i=2
$ k=3
$ awk -v i="$i" -v k="$k" -F:: '$1==k{n=NR+i} n==NR' file
/etc/security/limits.d/test
How it works:
-v i="$i" -v k="$k"
These options set awk variable i and k to the values of the shell variables $i and $k, respectively.
-F::
This sets the field separator to ::.
$1==k {n=NR+i}
If the first field of the current line equals the variable k, then set variable n to the current line number, NR, plus i.
n==NR
If the current line number, NR, is n, then print this line.

Answer 2

With sed:
$ id=3; sed -En "/^$id::/,/^$/{/^[[:blank:]]*\//p}" jenny
/etc/security/limits.conf
/etc/security/limits.d/test
Explanations:
Your shell will interpret the command and replace id by its value.
/^$id::/,/^$/{} the scope {} will be executed only between the lines that starts with the value of id followed by :: (/^$id::/) until an empty line (/^$/)
/^[[:blank:]]*\//p for the lines that start with some POSIX blank character class (e.g. space/tab) followed by / print the line. This will print your two paths.
To specify a line:
$ id=3; line=1; sed -En "/^$id::/,/^$/{/^[[:blank:]]*\//p}" jenny | cut -d$'\n' -f"$line"
/etc/security/limits.conf
$ id=3; line=2; sed -En "/^$id::/,/^$/{/^[[:blank:]]*\//p}" jenny | cut -d$'\n' -f"$line"
/etc/security/limits.d/test
$ id=3; line=1; sed -En "/^$id::/,/^$/{/^[[:blank:]]*\//p}" jenny | sed -n "${line}p"
/etc/security/limits.conf
$ id=3; line=2; sed -En "/^$id::/,/^$/{/^[[:blank:]]*\//p}" jenny | sed -n "${line}p"
/etc/security/limits.d/test

Answer 3

Assuming you want to build onto your previous question rather than coming up with a completely different approach
$ awk -v id=3 -v lineNr=1 -v RS= -F '::' '$1==id{ split($3,lines,/\n/); print lines[lineNr+1] }' file
/etc/security/limits.conf
$ awk -v id=3 -v lineNr=2 -v RS= -F '::' '$1==id{ split($3,lines,/\n/); print lines[lineNr+1] }' file
/etc/security/limits.d/test