Should I use the readonly flag?
bash
Solution
`readonly` is useful for some variables that are set by bash, for example `$UID` - non-readonly values like `$LOGNAME` and `$USER` are easy for the user to alter. If you find `readonly` useful then use it! Not many people use `readonly`, but don't let that bother you. Downside - like other variable attributes, `readonly` attribute is not passed on with an exported variable, unless the child process is another bash. One use of `readonly` is to apply it to a function. That's not widely done, but it solves a support issue of (by mistake) having two functions of the same name, which can be an issue when using functions stored outside the script. ksh also supports `readonly` (as an alias).
Problem
Yesterday I've discovered that Bash provides a means to mark variables as read-only, using the readonly keyword: ``` readonly hello="hello" hello="world" # error message, Bash refuses to reassign the variable ``` This seems like a nice feature, still, I've never seen this used in any Bash script. Is there any reason not to use this extensivly? Is it actually portable?