Added a simple shell, jsh

1 files changed, 54 insertions, 0 deletions

diff --git a/src/cmd/cat/cat.c b/src/cmd/cat/cat.c
new file mode 100755
index 0000000..1c3e40a
--- /dev/null
+++ b/src/cmd/cat/cat.c
@@ -0,0 +1,54 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdbool.h>
+
+void fileoutput(FILE *, const char *);
+bool isdir(const char *);
+
+/* concatinate files to a file stream */
+int main(int argc, char **argv)
+{
+	FILE *fp;
+	if (argc == 1) {
+		fileoutput(stdin, "stdin");
+	} else {
+		while (--argc > 0 && !ferror(stdout)) {
+			if (isdir(*++argv)) {
+				perror("cat");
+				continue;
+			}
+			if ((fp = fopen(*argv, "r")) == NULL) {
+				perror("cat");
+				continue;
+			}
+			fileoutput(fp, *argv);
+		}
+	}
+	if (ferror(stdout)) {
+		perror("cat");
+		return -1;
+	}
+	return 0;
+}
+
+/* fileoutput: output a file to stdout */
+void fileoutput(FILE *fp, const char *name)
+{
+	int c;
+	while ((c = getc(fp)) != EOF)
+		putc(c, stdout);
+	if (ferror(fp)) {
+		perror("cat");
+	}
+	fclose(fp);
+}
+
+/* isdir: return true if the file as the path is a directory */
+bool isdir(const char *path)
+{
+	struct stat sbuf;
+	stat(path, &sbuf);
+	return S_ISDIR(sbuf.st_mode);
+}
+