imakeidx Package ist file is not supported

Question

I am using imakeidx.sty package to generate two type of index like List of symbols, Index.

The problem is form.ist file is not working.

My form.ist file is

headings_flag 0
heading_prefix "{\\bfseries "
heading_suffix "}\\nopagebreak"
item_01 "\\nopagebreak\n \\subitem "
item_12 "\\nopagebreak\n \\subsubitem "
item_x1 "\\nopagebreak\n \\subitem "
item_x2 "\\nopagebreak\n \\subsubitem "
delim_0 "\\quad "
delim_1 "\\quad "
delim_2 "\\quad "

MWE:

\documentclass{article}

\usepackage{amsmath}
\usepackage{imakeidx}
\makeindex[name=symbols,title={List of symbols},options=makeindex -c -s form.ist symbols]
\makeindex[options=makeindex -c -s form.ist Sam_Ind]

\begin{document}

The sample\index[symbols]{$phi$} Index. The\index[symbols]{$\alpha$} sample Index. The sample Index. The sample Index. The sample Index. The sample Index. 

\newpage

The sample\index{Text Index One} Index two. The sample Index\index{Text Index two} two. The sample Index two. The sample Index two. The sample Index two. The sample Index two. 

\printindex[symbols]\markboth{List of symbols}{List of symbols} % Person index

\printindex

\end{document}

The options=makeindex -c -s form.ist symbols command is not working.

My required output is index entry and Page number in between seperator is \quad space.

But my current output is index entry and Page number in between seperator is ,.

I would like to control through the .ist file. But the .ind file is not updated.

My required output and current output mentioned below mentioned figure:

Please advice how to get the \quad space separation.

Answer 1

You're passing the whole command line, so what the system tries to do is

makeindex makeindex -c -s form.ist symbols symbols

which is an error.

The option key wants just the options to be passed to makeindex:

\usepackage{imakeidx}
\makeindex[name=symbols,title={List of symbols},options=-c -s form.ist]
\makeindex[options=-c -s form.ist]