Remove custom symbols

[Jom]

Hi.

1. I'm trying to create a template to remove spaces and hyphens. Here is my option:
exiftool "-TestName<${Model;s/ //g;s/-//g}" .
But I don't understand the purpose of "g".

2. Also, I don't understand fundamental difference between "tr" and "s" in the example from the documentation:
exiftool -p '${make;tr/ /_/;s/__+/_/g}' image.jpg
What are the cases where we can't use "s" instead of "tr"?

[StarGeek]

But I don't understand the purpose of "g".

The g stands for global.  Without it the substitution would stop after the first match.  For example if your regex was s/-// (no g), then "if-this-than-that" would be "if this-than-that", while with the g, it would be "if this than that".

2. Also, I don't understand fundamental difference between "tr" and "s" in the example from the documentation:
exiftool -p '${make;tr/ /_/;s/__+/_/g}' image.jpg
What are the cases where we can't use "s" instead of "tr"?

tr is the transliterate operator.  It replaces individual characters only. So if your example make was "Three   Spaces   Inbetween", then tr/ /_/ returns "Three___Spaces___Inbetween".  On the other hand, the other option is regex substitution.  It works likes this s/SearchTerm/Replacement/.  In the example s/__+/_/g it searches for an underscore (_) followed one or more underscores (_+).  The plus sign stands for 1 or more of the previous character.  So this command would take two or more underscores and globally replace them by a single underscore.  "Three___Spaces___Inbetween" becomes "Three_Spaces_Inbetween".

[Jom]

Спасибо за ответ.
It is very difficult to learn everything in a foreign language.

[StarGeek]

Sorry I can't be more helpful.  I tried to learn Russian years ago and failed spectacularly.  The only thing I remember is, roughly translated, "I don't know", "I don't understand" and "Please pass the glass".

[Jom]

"Please pass the glass".

You were taught by Russians when you drank vodka?

[StarGeek]

Heh, nope.  I'm a non-drinker.  I have no idea why that one stuck with me.

[Jom]

I'm also a non-drinker and non-smoker.
Real Russians do not drink and are not proud of vodka.
Ещё раз спасибо за ответы.