ruby , edit first line of multiple files in place with a ruby one-liner

## Question:

Tag: ruby

I can edit multiple files in place using the -p -i -e command line options:

ruby -pi -e 'sub(/a/,"b")' file*


How can I edit only the first line of each file? This works for one file only:

ruby -pi -e 'sub(/^/,"New line goes at top\n") if $. == 1' file1  This does not work: ruby -pi -e 'sub(/^/,"New line goes at top\n") if$. == 1' file*


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## edit first line of multiple files in place with a ruby one-liner

ruby
I can edit multiple files in place using the -p -i -e command line options: ruby -pi -e 'sub(/a/,"b")' file* How can I edit only the first line of each file? This works for one file only: ruby -pi -e 'sub(/^/,"New line goes at top\n") if \$. == 1' file1...

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