Question

I need to translate this piece of code from Perl to Lua

open(FILE, '/proc/meminfo');   
while(<FILE>)  
{  
    if (m/MemTotal/)  
    {  
        $mem = $_;  
        $mem =~ s/.*:(.*)/$1/;
    }  
    elseif (m/MemFree/)
    {
        $memfree = $_;
        $memfree =~ s/.*:(.*)/$1/;
    }
}
close(FILE);

So far I’ve written this

while assert(io.open("/proc/meminfo", "r")) do
    Currentline = string.find(/proc/meminfo, "m/MemTotal")
    if Currentline = m/MemTotal then
        Mem = Currentline
        Mem = string.gsub(Mem, ".*", "(.*)", 1)
    elseif m/MemFree then
        Memfree = Currentline
        Memfree = string.gsub(Memfree, ".*", "(.*)", 1)
    end
end
io.close("/proc/meminfo")

Now, when I try to compile, I get the following error about the second line of my code

luac: Perl to Lua:122: unexpected symbol near '/'

obviously the syntax of using a directory path in string.find is not like how I’ve written it. ‘But how is it?’ is my question.

Answer 1

To iterate a file line by line you can use io.lines.

for line in io.lines("/proc/meminfo") do
    if line:find("MemTotal") then --// Syntactic sugar for string.find(line, "MemTotal")
        --// If logic here...
    elseif --// I don't quite understand this part in your code.
    end
end

No need to close the file afterwards.