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Converts uppercase chars in a string to lowercase

Terminal - Converts uppercase chars in a string to lowercase
s="StrinG"; echo ${s,,}
2010-08-12 16:02:38
User: karpoke
Functions: echo
Converts uppercase chars in a string to lowercase

Another alternative is to define a function:

lower() {

echo ${@,,}


lower StrinG


There are 5 alternatives - vote for the best!

Terminal - Alternatives
echo StrinG | tr '[:upper:]' '[:lower:]'
echo StrinG | tr 'A-Z' 'a-z'
2010-08-12 15:42:56
User: randy909
Functions: echo tr

Another way to do it with slightly fewer characters. It doesn't work on Russian characters; please don't vote down because of that. :p It's very handy for those of us working in ascii :)

Know a better way?

If you can do better, submit your command here.

What others think

I'm getting:

-bash: ${s,,}: bad substitution

What is that trick? That syntax is foreign to me.

Comment by randy909 245 weeks and 3 days ago

I don't know why you get that "bad substitution". Are you running the bash shell or is it another one? I'm running bash v4.1.5.

This is a case of paremeter expansion of the form ${parameter,,pattern}. The , operator converts each matching uppercase letters to lowercase. When the pattern is omitted, it is treated like a ?, which matches every character.

More info in the section of "Parameter expansion" in the bash man page.

Comment by karpoke 245 weeks and 3 days ago

GNU bash, version 3.2.49(23)-release

Doesn't look like it supports the , operator. I tried to figure out another way to do it with parameter expansion in 3.2 but I couldn't see a way. Parameter expansion looks cool though, thanks for the help!

Comment by randy909 245 weeks and 3 days ago

its bash 4 syntax.

to uppercase conversion:

s="Test" ; echo ${s^^}

Comment by unefunge 231 weeks and 3 days ago

Your point of view

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