sed: Insert multiple lines before or after pattern match

Our requirement is to add multiple lines after a pattern is matched in a newline which can be before or after the match based upon the requirement



Below is our sample file /tmp/file
This is line one
This is line two
This is line three
This is line four
Here in we have to put below content
your text 1
your text 2
your text 3
as per below requirement

1. one line before the string is matched
2. one line after the string is matched

Example 1
Here we will add our content one line before the string is matched

Solution
# sed '/This is line two/i\your text 1\nyour text 2\nyour text 3' /tmp/file

This is line one
your text 1
your text 2
your text 3
This is line two
This is line three
This is line four
To do in place replacement
# sed -i '/This is line two/i\your text 1\nyour text 2\nyour text 3' /tmp/file
Example 2
Here we will add our content one line after the string is matched

Solution
# sed '/This is line two/a\your text 1\nyour text 2\nyour text 3' /tmp/file

This is line one
This is line two
your text 1
your text 2
your text 3
This is line three
This is line four
To do in place replacement
# sed -i '/This is line two/a\your text 1\nyour text 2\nyour text 3' /tmp/file
Example 3
You can add your content to a file for eg create a file /tmp/mydata with our content i.e.
your text 1
your text 2
your text 3
Now you can use below 'sed' command to append the content of "mydata" to /tmp/file"
# sed '/This is line two/r /tmp/mydata' /tmp/file

This is line one
This is line two
your text 1
your text 2
your text 3
This is line three
This is line four
To do in place replacement
# sed -i '/This is line two/r /tmp/mydata' /tmp/file

IMPORTANT NOTE:

Do not use this unless you are very sure the command will not impact anything else, it is always recommended to take a backup of such file where you plan to do in place replacement

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