How to quote arguments with xargs

I had a similar requirement and ended up using the -I switch to have a placeholder and I was able to quote it.

find . -size +1M | xargs -I {} rm "{}"

As you're already using that non-standard 1M, chances are your find implementation also supports -delete. So, simply use:

find . -type f -size +1M -delete

Where supported, that's by far the safest and most efficient.

If you insist on using xargs and rm with find, just add -print0 in your command:

find . -type f -size +1M -print0 | xargs -r0 rm -f --

(-print0 and -0 are non-standard, but pretty common. -r (to avoid running rm at all if find doesn't find anything) is less common, but if your xargs doesn't support it, you can just omit it, as rm with -f won't complain if called without argument).

The standard syntax would be:

find . -type f -size +1048576c -exec rm -f -- {} +

Other way:

find . -type f -size +1M -execdir rm -f -- {} +

(that's safer than -exec/xargs -0 and would work with very deep directory trees (where full file paths would end up larger than PATH_MAX), but that's also non-standard, and runs at least one rm for each directory that contains at least one big file, so would be less efficient).

From man find:

-print0

True; print the full file name on the standard output, followed by a null character (instead of the newline character that -print uses). This allows file names that contain newlines or other types of white space to be correctly interpreted by programs that process the find output. This option corresponds to the -0 option of xargs.

Option -0 of xargs means that output from pipe is interpreted as null terminated items. In such case you also need to create input for the pipe with find ... -print0.