Least changes needed to let Shellcheck parse to end

[gfoury]

Shellcheck is a tool for static analysis of various kinds of shell scripts. It has really helped me in the past. I would like it to run from beginning to end on ssdtPRGen.sh.

tl;dr:

Shellcheck gets stuck on some lines it considers syntax errors: parenthesized let expressions without quotes. This patch adds the quotes. You don't need to take the patch; you could use this branch in my repository to run Shellcheck.

Background

In ksh (I know we're in bash!) the following is a syntax error:

#!/bin/ksh
let a=(b*c)

whereas this is ok:

#!/bin/ksh
let a="(b*c)"

Shellcheck will barf and die on the first, even when it is checking Bash scripts. Shellcheck may be right or wrong, but in order to get all its other functionality, a few let expressions in ssdtPRGen.sh need to be tweaked. I decided the least-possible-change was double-quoting the expressions. Here are the other possibilities:

The parentheses don't do anything, so another way of rewriting is:

let a="$b * $c"

Bash numeric evaluation will dereference variables for you, so this does the same thing:

bash
let a="b * c"

I think that last one may be harder to read, since everywhere else variable dereferences are written `$foo`.

Finally, the really bash-y way of writing this is

``` bash
a=$(( b * c ))

[gfoury]

I added a makefile, with an easy way to tell Shellcheck to _SHUT UP_ about certain warnings. :-)