make directory if it doesn't exist with `mogrify -path` command

Question

I convert images in a directory named foo to bar by like this.

$ mkdir bar
$ mogrify -path bar -negate foo/*.png

Is there option in Imagemagick that create a folder with -path option, if it not exist.

Answer 1

To take arguments from the mogrify command, and do other actions based on their content, you can "override" the program with a function of your own, then pass the original arguments on to the function:

mymog(){
   [[ $1 == "-path" ]] && [[ ! -d $2 ]] && mkdir "$2" 
   mogrify "$@"
}

To use it, just replace mymog wherever you would use mogrify:

mymog -path bar -negate foo/*.png

The function tests to see if the first argument is -path. If so, it goes on to test if the second argument is not an existing directory. If it is not, then it creates that directory. (The [[ ]] && is just another way to write if-then statements.) In either case it goes on to pass all the arguments to the mogrify command.

The only warning is that you have to put the -path argument first -- you can't stick it elsewhere in the line. You should be able to use this wherever you would normally use mogrify and it will just ignore the mkdir part if there is no -path definition.

To have this available in your daily usage, add those 4 lines to your .bash_profile or .bashrc file, depending on your operating system.

EDIT #2: New answer with no dependence on position of -path

function mogmod(){
    args=("$@")
    for ((i=0; i < $#; i++)) {
       if [[ ${args[$i]} = "-path" ]]
       then 
           mypath=${args[((i+1))]}
           [[ ! -d "$mypath" ]] && mkdir "$mypath" 
       fi
    }
    mogrify "$@"
}