Changing line (lowercase) in Bash 4.3.33 - incorrect replacement error
I am trying to change upper case to lower case using string substitution in bash, but I am getting a bad substitution error.
> a=HEY
> echo $a
HEY
> echo ${a,,}
-bash: ${a,,}: bad substitution
# desired output is hey
I've seen similar questions to this, but most of the time it didn't use an earlier version of bash. I am using GNU bash 4 and am still having the same problems.
> bash --version
GNU bash, version 4.3.33(1)-release (x86_64-apple-darwin14.1.0)
Could it be a Mac? Any help would be appreciated.
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It looks like the bash that is first in PATH
will be 4.3.33, but the bash you are using in an interactive session is probably an older version. Run echo "$BASH_VERSION"
to check.
If this is true, run
type bash
to see the path to a newer version, maybe something like /opt/local/bin/bash
. I guess that's the way it is. If you want this to be your login shell, first add it to / etc / shells
sudo -e /etc/shells
After that, users are allowed to select this as their login shell using the command chsh
( ch ange sh ell)
chsh -s /opt/local/bin/bash
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