gnuplot - Plus-minus symbol in legend using terminal pngcairo -

I have a Gnuplot script, which has a key (legend), and I want the legend plus or minus symbol .

I found that I can use it (see script below), but it is a bit slow. I can only get it to work if I have an underscore before the title of Legend, it is okay, because I want to use the subscript feature but I want all the "Magazine" to be subscripted. At the time I had this time, only M subscript has been done. I tried to use "Mag" and (Meg) but neither worked. Do you know how I can get a complete magazine?

I have tried to remove any unnecessary script, but do not want to remove everything when used to solve this problem: / P>

  MonitorSys = System ("Exercise | Azak / / * / {sub (/ x /, \", \ "); print $ 1; exit} '') set macros set terminal pngcairo size @ monitor size dabbed enhanced set style line 3 PT1 PS 0.5 LT1 LW 2 LC RGB "green" set encoding ISO_885 9_1 plot path_to_data Using each: 1: 1:18 wl ls 3 heading 'U_mag \ 261 2' set output 'test_2.png In general, I will post separate posts in separate questions, but I think it is related , So I will post it here. I hope that's okay.  
 When I run the script from the terminal (but on scientific Linux), I get completely gobbledge.  
 Then, the following characters on the command line: 62; 9; c do you know Why is this so and do you know how can I send Gabbeldeq to the terminal?  
 When I run the script without underscores, the title below, me plus or minus Symbol does not get. I still get the gobbledge, but I do not get "62; 9; c" on the command line.  
  Monitor = System (Set up "Exant | AZ" / \ * / {sub (/ x /, \ ", \"); print $ 1; exit} ') Set macros set terminal Set pngcairo size @monitorSize steamed extended set style line 3 pt 1 ps 0.5 lt 1 lw 2 lc rgb "green" set encoding iso_8859_1 Plot path_to_data Each :: 1 1:18 wl ls 3 using the title 'Umag \ 261 2 'Set output' test_1.png 'replot  
 
 I give 2 figures: showing the first script in the first script; Showing the output from the second second script. 
 
  
 
  
 
 Thank you for your help! The following script works fine for me using 4.6.5: 
 
 
 Set Terminal Pngcairo size 600,200 set Output 'plus-minus.png' Set encoding iso_8859_1 Plot -x title "\ 261"  
 
 Definitely you set either directly to  Using encoding Iso_8859_1 , or  set encoding utf8 . 
 
  
 
 you actually plot The output file should be set  , as I do in the above script, in your case, the whole PNG file is printed in the standout, i.e. in your terminal and only the  report  Redirects the image data to the actual file.