Print footer with column numbers - linux

Question

I found this command {print NF} to show total number of columns:
$ nova list | awk '{print NF}' | sort -n | uniq
1
9
10
But I wish to print for every column their number.
See example with field separator |:
$ nova list | head
+--------------------------------------+-----------------------------------------+--------+----------------------------------------------+
| ID | Name | Status | Networks |
+--------------------------------------+-----------------------------------------+--------+----------------------------------------------+
| 45bd0bc3-96b4-4193-ae76-59115b4ee528 | rert | ACTIVE | netblock5=192.168.0.10 |
| 6682aa37-b766-437e-9b16-ce1076ce2410 | test5 | ACTIVE | netblock5=192.168.0.110 |
| 6f08fcf3-ea71-4f33-a01a-9b0712385511 | test2 | ACTIVE | netblock5=192.168.0.111 |
| 8f628408-1ace-4792-85b6-e134fe1f07cb | test55 | ACTIVE | netblock5=192.168.0.52, 192.168.222.46 |
| 458aa8cb-42c2-4aa6-ab30-c6858bcd85f3 | derggdre | ACTIVE | netblock5=192.168.0.63, 192.168.222.49 |
| 67f4bd0c-0e4d-4ba1-8765-dc7d7831c8f8 | dgrfdrf | ACTIVE | netblock5=192.168.1.86 |
| 846ffa7d-76a4-4c70-8d82-23b5a205ad77 | ttttt | ACTIVE | netblock5=192.168.1.27 |
1 2 3 4

Answer 1

Let just understand what awk is doing here
nova list | awk '{print NF}' | sort -n | uniq
here in awk '{printf NF}' NF is number of fields where the field separator is taken as space. So in output below NF=9 (count pipe '|' symbol also).
| ID | Name | Status | Networks |
and same goes for below data line
| 846ffa7d-76a4-4c70-8d82-23b5a205ad77 | ttttt | ACTIVE | netblock5=192.168.1.27 |
In your output you are getting 1 and 10 also some line in nova list command output must have single field or 10 fields.
Now coming to your problem you wish to print field with its NF or field value with its NF value.
nova list | awk '{for(I=1;I<=NF;I++){printf I"-"$I" "}printf "\n"}'
It will not print the field number in last of the file but with the data.

Answer 2

Perl to the rescue:
nova list | \
perl -ne 'print;
$s = $_ if /\|/;
}{
$s =~ s/[^|]/ /g;
$s =~ s/\|/++$i/ge;
print " $s\n"
'
-n reads the input line by line
each line is printed and remembered in $s if it contains | (to skip the final border)
when the input ends }{, everything that's not a | is replaced by a space
all | are replaced by numbers
the result is printed
More tweaking needed if the number of columns > 10 (numbers get wider than 1 char):
$s =~ s/(??{" {".((length(0+$i))-1)."}"})\|/++$i/ge;

Answer 3

nova list | {
read line; echo "$line" # read and print the first line
read header; echo "$header" # read, remember and print the 2nd line
cat # all the rest of the nova list output
# then, use the header, and transform the words into numbers
echo "$header" | perl -pe 's/(\w+)/ sprintf "%-*d", length($1), ++$n /ge';
}
output
+--------------------------------------+-----------------------------------------+--------+----------------------------------------------+
| ID | Name | Status | Networks |
+--------------------------------------+-----------------------------------------+--------+----------------------------------------------+
| 45bd0bc3-96b4-4193-ae76-59115b4ee528 | rert | ACTIVE | netblock5=192.168.0.10 |
| 6682aa37-b766-437e-9b16-ce1076ce2410 | test5 | ACTIVE | netblock5=192.168.0.110 |
| 6f08fcf3-ea71-4f33-a01a-9b0712385511 | test2 | ACTIVE | netblock5=192.168.0.111 |
| 8f628408-1ace-4792-85b6-e134fe1f07cb | test55 | ACTIVE | netblock5=192.168.0.52, 192.168.222.46 |
| 458aa8cb-42c2-4aa6-ab30-c6858bcd85f3 | derggdre | ACTIVE | netblock5=192.168.0.63, 192.168.222.49 |
| 67f4bd0c-0e4d-4ba1-8765-dc7d7831c8f8 | dgrfdrf | ACTIVE | netblock5=192.168.1.86 |
| 846ffa7d-76a4-4c70-8d82-23b5a205ad77 | ttttt | ACTIVE | netblock5=192.168.1.27 |
| 1 | 2 | 3 | 4 |
Actually, I can put that all is a quick perl script:
echo "$nova_list" | perl -ne '
$header = $_ if $. == 2;
print;
} {
$header =~ s/(\w+)/ sprintf "%-*d", length($1), ++$n /ge;
print $header;
'

Answer 4

You can get the last line of the file and "clean" it so that it becomes the footer with the field numbers:
nova list | awk -F"|" '1;
END {gsub (/[^|]/," ")
for(i=1;i<=NF;i++)
sub(/\| /, " " i)
gsub(/\|/," ")
print
}'
This:
replaces everything but | with a space.
replaces all strings "| " with an autoincremented number.
replaces the trailing |.
prints the result.
Test
$ cat a
+--------------------------------------+-----------------------------------------+--------+----------------------------------------------+
| ID | Name | Status | Networks |
+--------------------------------------+-----------------------------------------+--------+----------------------------------------------+
| 45bd0bc3-96b4-4193-ae76-59115b4ee528 | rert | ACTIVE | netblock5=192.168.0.10 |
| 6682aa37-b766-437e-9b16-ce1076ce2410 | test5 | ACTIVE | netblock5=192.168.0.110 |
| 6f08fcf3-ea71-4f33-a01a-9b0712385511 | test2 | ACTIVE | netblock5=192.168.0.111 |
| 8f628408-1ace-4792-85b6-e134fe1f07cb | test55 | ACTIVE | netblock5=192.168.0.52, 192.168.222.46 |
| 458aa8cb-42c2-4aa6-ab30-c6858bcd85f3 | derggdre | ACTIVE | netblock5=192.168.0.63, 192.168.222.49 |
| 67f4bd0c-0e4d-4ba1-8765-dc7d7831c8f8 | dgrfdrf | ACTIVE | netblock5=192.168.1.86 |
| 846ffa7d-76a4-4c70-8d82-23b5a205ad77 | ttttt | ACTIVE | netblock5=192.168.1.27 |
See output:
$ awk -F"|" '1; END {line=$0; fields=NF; gsub (/[^\|]/," "); for(i=1;i<=fields;i++) sub(/\| /, " " i); gsub(/\|/," "); print}' a
+--------------------------------------+-----------------------------------------+--------+----------------------------------------------+
| ID | Name | Status | Networks |
+--------------------------------------+-----------------------------------------+--------+----------------------------------------------+
| 45bd0bc3-96b4-4193-ae76-59115b4ee528 | rert | ACTIVE | netblock5=192.168.0.10 |
| 6682aa37-b766-437e-9b16-ce1076ce2410 | test5 | ACTIVE | netblock5=192.168.0.110 |
| 6f08fcf3-ea71-4f33-a01a-9b0712385511 | test2 | ACTIVE | netblock5=192.168.0.111 |
| 8f628408-1ace-4792-85b6-e134fe1f07cb | test55 | ACTIVE | netblock5=192.168.0.52, 192.168.222.46 |
| 458aa8cb-42c2-4aa6-ab30-c6858bcd85f3 | derggdre | ACTIVE | netblock5=192.168.0.63, 192.168.222.49 |
| 67f4bd0c-0e4d-4ba1-8765-dc7d7831c8f8 | dgrfdrf | ACTIVE | netblock5=192.168.1.86 |
| 846ffa7d-76a4-4c70-8d82-23b5a205ad77 | ttttt | ACTIVE | netblock5=192.168.1.27 |
1 2 3 4
Or keeping the field separators:
$ awk -F"|" '1; END {line=$0; fields=NF; gsub (/[^\|]/," "); for(i=1;i<=fields;i++) sub(/\| /, "| " i); print}' a
+--------------------------------------+-----------------------------------------+--------+----------------------------------------------+
| ID | Name | Status | Networks |
+--------------------------------------+-----------------------------------------+--------+----------------------------------------------+
| 45bd0bc3-96b4-4193-ae76-59115b4ee528 | rert | ACTIVE | netblock5=192.168.0.10 |
| 6682aa37-b766-437e-9b16-ce1076ce2410 | test5 | ACTIVE | netblock5=192.168.0.110 |
| 6f08fcf3-ea71-4f33-a01a-9b0712385511 | test2 | ACTIVE | netblock5=192.168.0.111 |
| 8f628408-1ace-4792-85b6-e134fe1f07cb | test55 | ACTIVE | netblock5=192.168.0.52, 192.168.222.46 |
| 458aa8cb-42c2-4aa6-ab30-c6858bcd85f3 | derggdre | ACTIVE | netblock5=192.168.0.63, 192.168.222.49 |
| 67f4bd0c-0e4d-4ba1-8765-dc7d7831c8f8 | dgrfdrf | ACTIVE | netblock5=192.168.1.86 |
| 846ffa7d-76a4-4c70-8d82-23b5a205ad77 | ttttt | ACTIVE | netblock5=192.168.1.27 |
| 1 | 2 | 3 | 4 |