Merge

Yaml files can be merged using the 'merge' command. Each additional file merged with the first file will set values for any key not existing already or where the key has no value.

yq m <yaml_file> <path>...

To Stdout¶

Given a data1.yaml file of:

a: simple
b: [1, 2]

and data2.yaml file of:

a: other
c:
  test: 1

then

yq m data1.yaml data2.yaml

will output:

a: simple
b: [1, 2]
c:
  test: 1

Updating files in-place¶

Given a data1.yaml file of:

a: simple
b: [1, 2]

and data2.yaml file of:

a: other
c:
  test: 1

then

yq m -i data1.yaml data2.yaml

will update the data1.yaml file so that the value of 'c' is 'test: 1'.

Overwrite values¶

Given a data1.yaml file of:

a: simple
b: [1, 2]

and data2.yaml file of:

a: other
c:
  test: 1

then

yq m -x data1.yaml data2.yaml

will output:

a: other
b: [1, 2]
c:
  test: 1

Overwrite values with arrays¶

Given a data1.yaml file of:

a: simple
b: [1, 2]

and data3.yaml file of:

b: [3, 4]
c:
  test: 2
  other: true
d: false

then

yq m -x data1.yaml data3.yaml

will output:

a: simple
b: [3, 4]
c:
  test: 2
  other: true
d: false

Notice that 'b' does not result in the merging of the values within an array.

Append values with arrays¶

Given a data1.yaml file of:

a: simple
b: [1, 2]
d: hi

and data3.yaml file of:

a: something
b: [3, 4]
c:
  test: 2
  other: true

then

yq m -a data1.yaml data3.yaml

will output:

a: simple
b: [1, 2, 3, 4]
c:
  test: 2
  other: true
d: hi

Note that the 'b' array has concatenated the values from the second data file. Also note that other map keys are not overridden (field a).

Append cannot be used with overwrite, if both flags are given then append is ignored.

Multiple Documents - merge into single document¶

Currently yq only has multi-document support for the first document being merged into. The remaining yaml files will have their first document selected.

Given a data1.yaml file of:

something: else
---
a: simple
b: cat

and data3.yaml file of:

b: dog

then

yq m -x -d1 data1.yaml data3.yaml

will output:

something: else
---
a: simple
b: dog

Multiple Documents - merge into all documents¶

Currently yq only has multi-document support for the first document being merged into. The remaining yaml files will have their first document selected.

Given a data1.yaml file of:

something: else
---
a: simple
b: cat

and data3.yaml file of:

b: dog

then

yq m -x -d'*' data1.yaml data3.yaml

will output:

b: dog
something: else
---
a: simple
b: dog