pschdir(1)

pschdir/Makefile

@@ -0,0 +1,2 @@
+pschdir: pschdir.c
+	$(CC) $(CFLAGS) -o pschdir pschdir.c

pschdir/pschdir.c

@@ -0,0 +1,41 @@
+#include <errno.h> /* EACCESS, ELOOP, ENAMETOOLONG, ENOENT, ENOTDIR, errno */
+#include <stdio.h> /* fprintf(3) */
+#include <stdlib.h> /* stderr */
+#include <sysexits.h> /* EX_OSERR, EX_NOPERM, EX_NOINPUT, EX_UNAVAILABLE,
+                       * EX_USAGE */
+#include <unistd.h> /* chdir(2) */
+
+static char *program_name = "pschdir";
+
+int main(int argc, char *argv[]){
+
+	if(argc < 3){
+		fprintf(stderr,
+			"Usage: %s [directory] [command (argument...)]\n",
+			argv[0] == NULL ? program_name : argv[0]);
+		return EX_USAGE;
+	}
+
+	if(chdir(argv[1]) != 0){
+		fprintf(stderr, "%s: %s: ", argv[0], argv[1]);
+		switch(errno){
+		case EACCES:
+			fprintf(stderr, "Access to directory denied.\n");
+			return EX_NOPERM;
+		case ELOOP:
+			fprintf(stderr, "Symbolic link loop.\n");
+			return EX_UNAVAILABLE;
+		case ENAMETOOLONG:
+			fprintf(stderr, "Name too long.\n");
+			return EX_OSERR;
+		case ENOENT:
+			fprintf(stderr, "Not found.\n");
+			return EX_NOINPUT;
+		case ENOTDIR:
+			fprintf(stderr, "Not a directory.\n");
+			return EX_NOINPUT;
+		}
+	}
+
+	execvp(argv[2], argv + 2);
+}