Strip newlines from terminal output
Every so often I will need to take some kind of key file - like a PGP key, SSH, OpenSSL, that kind of thing, and be able to paste it into a one-line text entry somewhere. Maybe a .env file, or shell script, or some piece of infrastructure that just accepts a text field as the input (like CI configuration).
I’ve always had to google for how to remove newlines from such a file, and I’ve seen a range of
awk, all of that sort of thing.
I’ve just been able to find an easier way, which I’m documenting here, because I want to remember it for next time.
To remove newlines from a key-type file:
cat ~/.ssh/id_rsa.pub | tr -d '\n'
cat- stream the file into the pipe
tr- “ tr - translate or delete characters”
-d- delete the character, don’t try and replace it
'\n'- the character to delete (must be in single quotes to avoid your shell trying to interpret it).
Since I have
pbcopy available on my laptop, I can easily copy this to my clipboard:
cat ~/.ssh/id_rsa.pub | tr -d '\n' | pbcopy
(I’m on Linux, but have an alias for pbcopy so it behaves the same way as it would on Mac OS).
Or base 64 encode it first:
cat ~/.ssh/id_rsa | base64 | tr -d '\n' | pbcopy