Implement -e support for grep
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sin
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82bff35228
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9
grep.1
9
grep.1
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@ -4,6 +4,8 @@ grep \- search files for a pattern
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.SH SYNOPSIS
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.B grep
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.RB [ \-Ecilnqv ]
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.RB [ \-e
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.I pattern ]
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.I pattern
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.RI [ file ...]
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.SH DESCRIPTION
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@ -25,6 +27,13 @@ matches using extended regex.
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.B \-c
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prints only a count of matching lines.
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.TP
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.B \-e pattern
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Specify a pattern used during the search of the input: an input
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line is selected if it matches any of the specified patterns.
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This option is most useful when multiple -e options are used to
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specify multiple patterns, or when a pattern begins with a dash
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(`-').
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.TP
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.B \-i
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matches lines case insensitively.
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.TP
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129
grep.c
129
grep.c
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@ -10,19 +10,27 @@
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enum { Match = 0, NoMatch = 1, Error = 2 };
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static void grep(FILE *, const char *, regex_t *);
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static void addpattern(const char *);
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static bool grep(FILE *, const char *);
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static void usage(void);
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static bool eflag = false;
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static bool vflag = false;
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static bool many;
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static bool match = false;
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static char mode = 0;
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static struct plist {
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char *pattern;
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regex_t preg;
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struct plist *next;
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} *phead;
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int
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main(int argc, char *argv[])
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{
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bool match = false;
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struct plist *pnode, *tmp;
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int i, n, flags = REG_NOSUB;
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regex_t preg;
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FILE *fp;
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ARGBEGIN {
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@ -30,6 +38,10 @@ main(int argc, char *argv[])
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flags |= REG_EXTENDED;
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break;
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case 'c':
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case 'e':
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addpattern(EARGF(usage()));
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eflag = true;
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break;
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case 'l':
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case 'n':
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case 'q':
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@ -45,57 +57,97 @@ main(int argc, char *argv[])
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usage();
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} ARGEND;
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if(argc == 0)
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if(argc == 0 && !eflag)
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usage(); /* no pattern */
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if((n = regcomp(&preg, argv[0], flags)) != 0) {
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char buf[BUFSIZ];
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/* If -e is not specified treat it as if it were */
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if(!eflag) {
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addpattern(argv[0]);
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argc--;
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argv++;
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}
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regerror(n, &preg, buf, sizeof buf);
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enprintf(Error, "invalid pattern: %s\n", buf);
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/* Compile regex for all search patterns */
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for(pnode = phead; pnode; pnode = pnode->next) {
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if((n = regcomp(&pnode->preg, pnode->pattern, flags)) != 0) {
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char buf[BUFSIZ];
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regerror(n, &pnode->preg, buf, sizeof buf);
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enprintf(Error, "invalid pattern: %s\n", buf);
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}
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}
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many = (argc > 1);
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if(argc == 1)
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grep(stdin, "<stdin>", &preg);
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else for(i = 1; i < argc; i++) {
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if(!(fp = fopen(argv[i], "r")))
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enprintf(Error, "fopen %s:", argv[i]);
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grep(fp, argv[i], &preg);
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fclose(fp);
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if(argc == 0) {
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match = grep(stdin, "<stdin>");
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} else {
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for(i = 0; i < argc; i++) {
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if(!(fp = fopen(argv[i], "r")))
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enprintf(Error, "fopen %s:", argv[i]);
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if(grep(fp, argv[i]))
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match = true;
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fclose(fp);
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}
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}
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pnode = phead;
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while(pnode) {
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tmp = pnode->next;
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regfree(&pnode->preg);
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free(pnode->pattern);
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free(pnode);
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pnode = tmp;
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}
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return match ? Match : NoMatch;
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}
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void
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grep(FILE *fp, const char *str, regex_t *preg)
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addpattern(const char *pattern)
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{
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struct plist *pnode;
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pnode = malloc(sizeof(*pnode));
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if(!pnode)
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eprintf("malloc:");
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pnode->pattern = strdup(pattern);
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if(!pnode->pattern)
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eprintf("strdup:");
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pnode->next = phead;
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phead = pnode;
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}
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bool
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grep(FILE *fp, const char *str)
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{
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char *buf = NULL;
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long n, c = 0;
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size_t size = 0, len;
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struct plist *pnode;
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bool match = false;
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for(n = 1; afgets(&buf, &size, fp); n++) {
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if(buf[(len = strlen(buf))-1] == '\n')
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buf[--len] = '\0';
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if(regexec(preg, buf, 0, NULL, 0) ^ vflag)
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continue;
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switch(mode) {
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case 'c':
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c++;
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break;
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case 'l':
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puts(str);
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goto end;
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case 'q':
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exit(Match);
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default:
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if(many)
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printf("%s:", str);
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if(mode == 'n')
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printf("%ld:", n);
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printf("%s\n", buf);
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break;
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for(pnode = phead; pnode; pnode = pnode->next) {
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if(buf[(len = strlen(buf))-1] == '\n')
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buf[--len] = '\0';
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if(regexec(&pnode->preg, buf, 0, NULL, 0) ^ vflag)
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continue;
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switch(mode) {
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case 'c':
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c++;
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break;
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case 'l':
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puts(str);
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goto end;
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case 'q':
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exit(Match);
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default:
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if(many)
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printf("%s:", str);
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if(mode == 'n')
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printf("%ld:", n);
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printf("%s\n", buf);
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break;
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}
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match = true;
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}
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match = true;
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}
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if(mode == 'c')
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printf("%ld\n", c);
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@ -103,10 +155,11 @@ end:
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if(ferror(fp))
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enprintf(Error, "%s: read error:", str);
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free(buf);
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return match;
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}
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void
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usage(void)
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{
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enprintf(Error, "usage: %s [-Ecilnqv] pattern [files...]\n", argv0);
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enprintf(Error, "usage: %s [-Ecilnqv] [-e pattern] pattern [files...]\n", argv0);
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}
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