sed replace second occurrence in file not working

Question

I'm using centos 7. sed command to replace second occurrence not working to me. I tried the following solutions:

• Sed replace at second occurrence
• Sed/Awk to delete second occurence of string - platform independent
• sed: How to delete second match in a file
• https://unix.stackexchange.com/questions/18303/sed-delete-all-occurrences-of-a-string-except-the-first-one

The file:

this
foo
is
a test
file
this
foo

I am trying to run:

sed 's/foo/bar/2g' file
sed 's/foo/bar/2' file
sed -i 's/foo/bar/2g' file

I wish to replace all occurrences of "foo" with "bar" from the second one.

Answer 1

This might work for you (GNU sed):

sed -z 's/foo/bar/2' file

Slurps the whole for file into the pattern space and replaces the second occurrence of foo with bar.

Alternative:

sed 'H;$!d;x;s/.//;s/foo/bar/2' file