使用 sed 将 yaml 文件中的值替换为多行字符串

Question

I have been trying to replace/add value of a field in yaml with an env variable that has multi line string, using below syntax

replacewith=" |-
  multi
  line
  string"
sed -i -e "s/^\(\s*key-in-yaml\s*:\s*\).*/\1 $replacewith/"  somefile.yaml

We can assume that key-in-yaml doesn't have any value by default. Above comand results in

sed: -e expression #1, char 37: unterminated `s' command

I also want the indentation to be maintained.

If this is the content of yaml file

apiVersion: operators.coreos.com/v1alpha1
kind: ClusterServiceVersion
metadata:
  annotations:
    alm-examples:
    capabilities: Basic Install

after that sed command i was expecting

apiVersion: operators.coreos.com/v1alpha1
kind: ClusterServiceVersion
metadata:
  annotations:
    alm-examples: |-
      multi
      line
      string
    capabilities: Basic Install

Answer 1

With your shown samples, please try following, in case you are ok with awk .

awk -v str="$replacewith" '
1;
/annotations:/{ found=1 }
found && /alm-examples: \|-/{
  print str
  found=""
}
' Input_file

Once you are happy with above results(which will be shown on terminal) and in case you want to save them into Input_file itself then append > temp && mv temp Input_file to above command.

Answer 2

sed -E '/alm-examples/s/(.*)$/printf "\1 $replacewith"/e' somefile.yaml

This uses s///e to shell out to printf which will handle the multiline string better than attempts to inline it with sed commands. It is printf expanding the string, not sed , because the sed command is in single quotes.

This also works, with & replacing the \1 , because the line break doesn't get passed to printf either way:

sed -E '/alm-examples/s/.*/printf "& $replacewith"/e' somefile.yaml

Or, to depend on annotations: in the prior line:

sed -E '/annotations:/{N;/alm-examples/s/.*/printf "& $replacewith"/e}' somefile.yaml

Answer 3

I have decided to use yq and it has been working great even for complex fields in yaml for example abc[0].d=env-var-multiline .