#check if the name is valid
function myfunc()
{
#check "${1}"
#echo "valid/invalid"
}
#these should return valid
myfunc "my_number"
myfunc "my_number1"
#these should return ivalid
myfunc "1my_number"
myfunc "1my _number"
myfunc "my number"
myfunc "my_number?"
and so on the variable name can have only letters , numbers (but not on the beginning),.. and like all the rules for java...
Is there any function that I can use ? I do not want to reinvent the wheel...
Match the variable name against a regex, like this:
myfunc() {
if [[ "$1" =~ ^[a-z][a-zA-Z0-9_]*$ ]]
then
echo "$1: valid"
else
echo "$1: invalid"
fi
}
^[a-z][a-zA-Z0-9_]*$ would mark variables starting with an uppercase character invalid. May I suggest ^[a-zA-Z][a-zA-Z0-9_]*$?
^[_[:alpha:]][_[:alnum:]]*$ If you want to match case-insensitively, you can shopt -s nocasematchdogbane's answer is almost complete for the context of bash variables, but it has not been updated to reflect the final comment which contains a fully working validator. According to his comment on his answer, this is intended. This answer provides a function which evaluates to true for all valid names and can be used as a condition rather than returning a value that must then be compared to something. Plus, it can be used across multiple shells.
The function:
isValidVarName() {
echo "$1" | grep -q '^[_[:alpha:]][_[:alpha:][:digit:]]*$'
}
Example usage in bash:
key=...
value=...
if isValidVarName "$key"; then
eval "$key=\"$value\""
fi
# or it might simply look like this
isValidVarName "$key" && eval "$key=\"$value\""
[:alnum:] instead of [:alpha:][:digit:]? For instant I suggest '[[:alpha:]_][[:alnum:]_]*$' which is more concise.Bash only:
isvalidvarname ()
{
local varname;
local regexp_varname='^[_[:alpha:]][_[:alpha:][:digit:]]*$';
varname="$1";
[[ "${varname}" =~ ${regexp_varname} ]]
}
A combination of already proposed answers. For all shells, by using grep:
is_valid_name() { # NAME
printf '%s' "$1" | grep --quiet '^[_[:alpha:]][_[:alpha:][:digit:]]*$'
}
For shells that accept regexp, like Bash:
function is_valid_name { # NAME
[[ "$1" =~ ^[_[:alpha:]][_[:alpha:][:digit:]]*$ ]]
}
Both return 0 (true) if NAME is a valid variable name, else return 1 (false). They can be used like this:
NAME='...'
is_valid_name "$NAME" && ...
if is_valid_name "$NAME"; then
...
fi