Given these files in in/,
$ find -type f | sort
./in/x/y/z1/i.jpg
./in/x/y/z2/i.jpg
./in/x/y/z3/i.jpg
./in/x/y/z4/i.jpg
./in/x/y/z5/i.jpg
I would like use GNU parallel to convert all JPEGs to PNGs, to create
./out/z1/png/i.png
./out/z2/png/i.png
./out/z3/png/i.png
./out/z4/png/i.png
./out/z5/png/i.png
My non-working solution so far, where <???> should be the zX path component from the input path:
find -type f | parallel "convert {} /path/to/out/<???>/png/{/.}.png"
In GNU parallel, how to extract the n-th path component from the input path? I.e. how do I get the zX part from ./in/x/y/zX/i.jpg?
Update: I do not want to export a function.
Use a perl expression replacement string
find -type f | parallel 'echo convert {} /path/to/out/{= s:.*/([^/]*)/[^/]*:\1: =}/png/{/.}.png'
prints
convert ./in/x/y/z1/i.jpg /path/to/out/z1/png/i.png
convert ./in/x/y/z2/i.jpg /path/to/out/z2/png/i.png
convert ./in/x/y/z3/i.jpg /path/to/out/z3/png/i.png
convert ./in/x/y/z4/i.jpg /path/to/out/z4/png/i.png
convert ./in/x/y/z5/i.jpg /path/to/out/z5/png/i.png
If this is what you want, then remove the echo.