sed: capitalizing the first letter of a line

[sha1sum]

Hello guys,

I'd like to instruct sed to capitalize the first letter of every line. I've gotten this far:


$ echo "the first word is not capitalized." | sed 's/^t/T/'
The first word is not capitalized.


That seems to work (yay!). Say I'd like to do it for multiple different lines of text, then of course I could do something like this:

$ cat bigstory.txt | sed 's/^a/A/; s/^b/B/; s/^c/C/; s/^d/D/; s/^e/E/'
etcetera, and make a huge command. But that is not very elegant. There has to be a nice way to do it. Do you know one?

[Bachstelze]

I know I'm not supposed to say this but... Google is your friend, really.


sed -e 's/^\(.\)/\U\1/g' foo.txt

This seems to be non-standard, I do not know the standard way.

[steeldriver]

There's a special instruction \u for that - combined with the & which substitutes the whole pattern found



$ echo "the first word is not capitalized." | sed 's/.*/\u&/'
The first word is not capitalized.


FYI, to capitalize the whole thing it's \U



$ echo "the first word is not capitalized." | sed 's/.*/\U&/'
THE FIRST WORD IS NOT CAPITALIZED.

[sha1sum]

Thanks guys. I'm learning how to use the command line, this helps. sed seems to be a difficult command to work with, the way it takes arguments appears so random.


I know I'm not supposed to say this but... Google is your friend, really.
I'll try to do that more in the future.

[Bachstelze]

sed is not just a "command", for most intents and purposes you can treat it as a programming language in its own right.

[vasa1]

I know I'm not supposed to say this but... Google is your friend, really.


sed -e 's/^\(.\)/\U\1/g' foo.txt

This seems to be non-standard, I do not know the standard way. Why do you say it's non-standard? And why have g when it's just the first occurrence in a line that needs to be changed which seems to be taken care of by ^?

[Bachstelze]

Why do you say it's non-standard? And why have g when it's just the first occurrence in a line that needs to be changed which seems to be taken care of by ^?

I say it is non-standard because it does not work on non-GNU versions of sed. I use /g because I am not very good at sed. :)

[vasa1]

I say it is non-standard because it does not work on non-GNU versions of sed. ...
Thanks, I didn't know that :)

[sha1sum]

Well look at that. I ask a dumb question an now we've all learned something new. You're welcome. Hehe. :biggrin:

In the main time, I found this website that is very useful for sed: http://www.grymoire.com/Unix/Sed.html