1/* rev.c - reverse lines of a set of given input files 2 * 3 * Copyright 2012 Elie De Brauwer <eliedebrauwer@gmail.com> 4 5USE_REV(NEWTOY(rev, NULL, TOYFLAG_USR|TOYFLAG_BIN)) 6 7config REV 8 bool "rev" 9 default y 10 help 11 usage: rev [FILE...] 12 13 Output each line reversed, when no files are given stdin is used. 14*/ 15 16#include "toys.h" 17 18static void rev_line(char **pline, long len) 19{ 20 char *line; 21 long i; 22 23 if (!pline) return; 24 line = *pline; 25 if (len && line[len-1]=='\n') line[--len] = 0; 26 27 if (len--) for (i = 0; i <= len/2; i++) { 28 char tmp = line[i]; 29 30 line[i] = line[len-i]; 31 line[len-i] = tmp; 32 } 33 xputs(line); 34} 35 36void rev_main(void) 37{ 38 loopfiles_lines(toys.optargs, rev_line); 39} 40