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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2026 Richard QIn
*/
#include "ulib/stdio.h"
#include "ulib/stdlib.h"
#include "ulib/string.h"
#include "user/user.h"
#include "common/fcntl.h"
char buf[1024];
void grep(char *pattern, int fd)
{
int n, m;
char *p, *q;
m = 0;
while ((n = read(fd, buf + m, sizeof(buf) - m - 1)) > 0)
{
m += n;
buf[m] = '\0';
p = buf;
while ((q = strchr(p, '\n')) != 0)
{
*q = 0;
if (strstr(p, pattern) != 0)
{
printf("%s\n", p);
}
p = q + 1;
}
if (p == buf)
m = 0;
if (m > 0)
{
m -= p - buf;
memmove(buf, p, m);
}
}
}
int main(int argc, char *argv[])
{
int fd, i;
char *pattern;
if (argc < 2)
{
printf("Usage: grep pattern [file...]\n");
exit(1);
}
pattern = argv[1];
if (argc == 2)
{
grep(pattern, 0); // stdin
exit(0);
}
for (i = 2; i < argc; i++)
{
if ((fd = open(argv[i], O_RDONLY)) < 0)
{
printf("grep: cannot open %s\n", argv[i]);
exit(1);
}
grep(pattern, fd);
close(fd);
}
exit(0);
}
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