Converts uppercase chars in a string to lowercase

s="StrinG"; echo ${s,,}
Another alternative is to define a function: lower() { echo ${@,,} } lower StrinG
Sample Output

By: karpoke
2010-08-12 16:02:38

2 Alternatives + Submit Alt

What Others Think

I'm getting: -bash: ${s,,}: bad substitution What is that trick? That syntax is foreign to me.
randy909 · 613 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.
karpoke · 613 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!
randy909 · 613 weeks and 3 days ago
its bash 4 syntax. to uppercase conversion: s="Test" ; echo ${s^^}
unefunge · 599 weeks and 3 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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