My sed command to insert lines into a file is not working - is special characters the issue? - bash

Question

I am trying to add a couple of lines in a text file with sed.
I think I have special characters that are giving me the issue.
I want to insert lines between
username: system:node:{{EC2PrivateDNSName}}
and
kind: ConfigMap
This is what I want to insert -
- groups:
- eks-role
- system:master
rolearn: arn:aws:iam::xxxxx:role/eks
username: eks
mapUsers: |
- userarn: arn:aws:iam::xxxxx:user/test-ecr
username: test-ecr
groups:
- eks-role
I have also tried using forward slashes around the special characters to no avail.
Here is the sed command I have now that does not work - it seems not to insert anything. I assume it can't find the line "username: system:node:{{EC2PrivateDNSName}}".
sed '/^username\: system:node\:{{EC2PrivateDNSName}}$/r'<(
echo " - groups:"
echo " - eks-role"
echo " - system:master"
echo " rolearn: arn:aws:iam::xxxxx:role/eks"
echo " username: eks"
echo " mapUsers: |"
echo " - userarn: arn:aws:iam::xxxxx:user/test-ecr"
echo " username: ecr"
echo " groups:"
echo " - eks-role"
) -i -- temp-aws-auth.yaml
Here is the contents of the file that I want to insert into -
apiVersion: v1
data:
mapRoles: |
- groups:
- system:bootstrappers
- system:nodes
rolearn: arn:aws:iam::xxxxx:role/eksctl-ops-nodegroup-linux-ng-sys-NodeInstanceRole-763ALQD2ZGXK
username: system:node:{{EC2PrivateDNSName}}
kind: ConfigMap
metadata:
creationTimestamp: "2020-12-09T15:54:56Z"
name: aws-auth
namespace: kube-system
resourceVersion: "1298"

Answer 1

UPDATE: Taking into consideration OPs answer/comment re: missing spaces, and a bit more fiddling, I was able to get the following sed command to work, too:
sed '/^.*username.*EC2PrivateDNSName.*$/r'<(cat replace.txt) temp-aws-auth.yaml
Assumptions:
OP is unable to use a yaml-aware tool to perform the edit
username ... EC2PrivateDNSName only shows up in one place in the file (or, alternatively, it shows up in multiple places and OP wishes to add a new line after each occurrence)
Replacement data:
$ cat replace.txt
- groups:
- eks-role
- system:master
rolearn: arn:aws:iam::xxxxx:role/eks
username: eks
mapUsers: |
- userarn: arn:aws:iam::xxxxx:user/test-ecr
username: test-ecr
groups:
- eks-role
NOTE: If the replacement data is in a variable it can fed into awk as a herestring.
One awk idea:
awk '
FNR==NR { a[FNR]=$0 # store first file (replacement data) into an array
next } # skip to next line in first file
{ print } # print current line of second file
/username.*EC2PrivateDNSName/ { for (i in a) # if we found our match then dump the contents of array a[] to stdout
print a[i]
next
}
' replace.txt temp-aws-auth.yaml
Or as a single-line:
awk 'FNR==NR {a[FNR]=$0; next} {print} /username.*EC2PrivateDNSName/ { for (i in a) print a[i]; next}' replace.txt temp-aws-auth.yaml
This generates:
apiVersion: v1
data:
mapRoles: |
- groups:
- system:bootstrappers
- system:nodes
rolearn: arn:aws:iam::xxxxx:role/eksctl-ops-nodegroup-linux-ng-sys-NodeInstanceRole-763ALQD2ZGXK
username: system:node:{{EC2PrivateDNSName}}
- groups:
- eks-role
- system:master
rolearn: arn:aws:iam::xxxxx:role/eks
username: eks
mapUsers: |
- userarn: arn:aws:iam::xxxxx:user/test-ecr
username: test-ecr
groups:
- eks-role
kind: ConfigMap
metadata:
creationTimestamp: "2020-12-09T15:54:56Z"
name: aws-auth
namespace: kube-system
resourceVersion: "1298"

Answer 2

I found out the issue with my original command - Sed needs the spaces included in the line it is looking for!
Since the line I was looking for has spaces in it :
' username: system:node:{{EC2PrivateDNSName}}'
I had to add the spaces to my sed statement :
sed '/^ username\: system:node\:{{EC2PrivateDNSName}}$/r'<(
Thanks for the feedback!
Happy holidays!!

Answer 3

This might work for you (GNU sed & cat):
cat <<\! |sed ':a;/username: system:node:{{EC2PrivateDNSName}}/{n;/kind: ConfigMap/!ba;h;s/.*/cat -/ep;g}' file
- groups:
- eks-role
- system:master
rolearn: arn:aws:iam::xxxxx:role/eks
username: eks
mapUsers: |
- userarn: arn:aws:iam::xxxxx:user/test-ecr
username: test-ecr
groups:
- eks-role
!
Make a here-document with the lines to be inserted.
Pipe the here-document through to a sed command.
If a line contains username: system:node:{{EC2PrivateDNSName}}, print it and fetch the next line.
If the following line does not contain kind: ConfigMap go to the start of the sed cycle and start again.
Otherwise, copy the current line, replace/print the current line by the lines to inserted from the here-document and then over write the replacement by the copy in the hold space.
N.B. The replacement lines are inserted into the document by way of the substitute command and the e flag, that evaluates what is substituted into the pattern space i.e. the cat - that is the here-document that is passed through via the pipe.