awk或sed命令基于定界符从文本文件中提取行

Question

My file say 'file.txt' has below content,

---
controller-name: RAID-1
host-power: on
has-error: No
info-valid: Yes
controller-health: Good
---
controller-name: RAID-2
host-power: on
has-error: No
info-valid: Yes
controller-health: Bad
...

I would like to extract lines using --- as the delimiter for each controller. Something like controller[0] will give me details of 1st controller and controller[1] of 2nd controller.

I tried to search but could not find any relevant answer.

Answer 1

Using awk

Based on some assumption, below 2 examples can be used to search controller config one by one, if this isn't a one which you are looking for edit, your question and brief us clearly.

Either

# which will print and exit
# search for controller-name, increment variable
# print contents and exit

awk -v controller=1 '
         f && /^---/{exit}
         /^controller-name/{c++}
         f=c==controller
       ' infile

Or

# which will save inside array
# used --- as row separator
# whenever controller-name awk finds, that line is saved in array
# in end block access it by a[0], a[1]....

awk -v RS='---' '
           /controller-name:/{
               gsub(/^\n|\n$/,"");
               a[c++]=$0
           }
           END{
              print a[0]
           }
          ' infile

Test Results:

Input:

$ cat infile 
---
controller-name: RAID-1
host-power: on
has-error: No
info-valid: Yes
controller-health: Good
---
controller-name: RAID-2
host-power: on
has-error: No
info-valid: Yes
controller-health: Bad
...

Output-1:

$ awk -v controller=1  'f && /^---/{exit}/^controller-name/{c++}f=c==controller' infile 
controller-name: RAID-1
host-power: on
has-error: No
info-valid: Yes
controller-health: Good

$ awk -v controller=2 'f && /^---/{exit}/^controller-name/{c++}f=c==controller' infile 
controller-name: RAID-2
host-power: on
has-error: No
info-valid: Yes
controller-health: Bad
...

Output-2:

$ awk -v RS='---' '/controller-name:/{gsub(/^\n|\n$/,"");a[c++]=$0}END{print a[0]}' infile 
controller-name: RAID-1
host-power: on
has-error: No
info-valid: Yes
controller-health: Good

$ awk -v RS='---' '/controller-name:/{gsub(/^\n|\n$/,"");a[c++]=$0}END{print a[1]}' infile 
controller-name: RAID-2
host-power: on
has-error: No
info-valid: Yes
controller-health: Bad
...