/* vi: set sw=4 ts=4: * * head.c - copy first lines from input to stdout. * * Copyright 2006 Timothy Elliott <tle@holymonkey.com> * * See http://www.opengroup.org/onlinepubs/009695399/utilities/head.html USE_HEAD(NEWTOY(head, "n#<0=10", TOYFLAG_BIN)) config HEAD bool "head" default y help usage: head [-n number] [file...] Copy first lines from files to stdout. If no files listed, copy from stdin. Filename "-" is a synonym for stdin. -n Number of lines to copy. */ #include "toys.h" DEFINE_GLOBALS( long lines; int file_no; ) #define TT this.head static void do_head(int fd, char *name) { int i, len, lines=TT.lines, size=sizeof(toybuf); if (toys.optc > 1) { // Print an extra newline for all but the first file if (TT.file_no++) xprintf("\n"); xprintf("==> %s <==\n", name); xflush(); } while (lines) { len = read(fd, toybuf, size); if (len<0) { perror_msg("%s",name); toys.exitval = EXIT_FAILURE; } if (len<1) break; for(i=0; i<len;) if (toybuf[i++] == '\n' && !--lines) break; xwrite(1, toybuf, i); } } void head_main(void) { loopfiles(toys.optargs, do_head); }