diff --git a/3-ShellPart1/dshlib.h b/3-ShellPart1/dshlib.h
new file mode 100644
index 0000000000000000000000000000000000000000..1353bbd3ba39a4099cdf58ab8f8827e2d3e4e5aa
--- /dev/null
+++ b/3-ShellPart1/dshlib.h
@@ -0,0 +1,50 @@
+#ifndef __DSHLIB_H__
+#define __DSHLIB_H__
+
+// Constants for command structure sizes
+#define EXE_MAX 64
+#define ARG_MAX 256
+#define CMD_MAX 8
+// Longest command that can be read from the shell
+#define SH_CMD_MAX EXE_MAX + ARG_MAX
+
+typedef struct command
+{
+    char exe[EXE_MAX];
+    char args[ARG_MAX];
+} command_t;
+
+typedef struct command_list
+{
+    int num;
+    command_t commands[CMD_MAX];
+} command_list_t;
+
+// Special character #defines
+#define SPACE_CHAR ' '
+#define PIPE_CHAR '|'
+#define PIPE_STRING "|"
+
+#define SH_PROMPT "dsh> "
+#define EXIT_CMD "exit"
+
+// Standard Return Codes
+#define OK 0
+#define WARN_NO_CMDS -1
+#define ERR_TOO_MANY_COMMANDS -2
+#define ERR_CMD_OR_ARGS_TOO_BIG -3
+
+// starter code
+#define M_NOT_IMPL "The requested operation is not implemented yet!\n"
+#define EXIT_NOT_IMPL 3
+#define NOT_IMPLEMENTED_YET 0
+
+// prototypes
+int build_cmd_list(char *cmd_line, command_list_t *clist);
+
+// output constants
+#define CMD_OK_HEADER "PARSED COMMAND LINE - TOTAL COMMANDS %d\n"
+#define CMD_WARN_NO_CMD "warning: no commands provided\n"
+#define CMD_ERR_PIPE_LIMIT "error: piping limited to %d commands\n"
+
+#endif
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