Maximum number of Bash arguments != max num cp arguments?
As Ignacio said, ARG_MAX is the maximum length of the buffer of arguments passed to exec(), not the maximum number of files (this page has a very in-depth explanation). Specifically, it lists fs/exec.c as checking the following condition:
PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *) / sizeof(void *)And, it seems, you have some additional limitations:
On a 32-bit Linux, this is ARGMAX/4-1 (32767). This becomes relevant if the average length of arguments is smaller than 4. Since Linux 2.6.23, this function tests if the number exceeds
MAX_ARG_STRINGSin<linux/binfmts.h>(2^32-1 = 4294967296-1). And as additional limit, one argument must not be longer thanMAX_ARG_STRLEN(131072).
ARG_MAX is the maximum length of the arguments to the exec(3) functions. A shell is not required to support passing this length of arguments from its command line.