Bash - Generate Camel Case from Underscore Words - Kotlin Friendly

Tuesday Feb 18, 2020

Lots of times I need to convert CSV headers that are lowercase with underscores to camel case. In other words, I’ll a header like first_name,last_name,date_of_birth and need to convert it to:

firstName,
lastName,
dateOfBirth

Even better, if I’m generating a Kotlin data class, I’ll generate:

var firstUname: String?,
var lastUname: String?,
var dateUofUbirth: String?

Then, I can just copy/paste into my Kotlin data class:

    data class User(
        var firstUname: String?,
        var lastUname: String?,
        var dateUofUbirth: String?,
    )

Here is the one-liner to do it:

 echo '"first_name","last_name","date_of_birth"' | \
 sed 's/"//g' |\
 tr , '\n' |\
 gsed -E 's/_(.)/\U\1/g' |\
 awk '{printf("var %s: String?,\n", $1);}'

Note If you’re on linux you can change the gsed to just sed and if you’re on mac you need to do brew install gnu-sed

Broken down:

You can adjust the last awk command to generate whatever you like, or remove it to just print one camel case phrase per line…

If you’re serious about Bash scripting - check one of these books out: