!: (Foreign) Conjunction
Interfaces with operating system services outside the provenance of J, e.g. system clock and file read/write, or with special J functionality relating to reading and setting global options and locale management.
m!:n y always requires integer values for m (section number) and n (function within the given section).
The value of y is conventionally set as '' unless the foreign requires explicit data
e.g. item names, file names.
Sometimes x is needed (but rarely). Otherwise it is omitted.
The function for given choice of m and n are well-documented in the J Dictionary Appendix A. Foreign Conjunction.
1. Return the time-of-day (optionally in a specified format)
See: 6!: Time
6!:0 '' 2007 10 30 13 10 45.312 6!:0 'hh:mm:ss MM/DD/YY' 13:10:48 10/30/07
2. Execute a given J script (silently)
See: 0!: Scripts
0!:0 <jpath '~temp/949.ijs'
Entry in the J Dictionary for !: