diff --git a/Makefile b/Makefile
index 4fc1b6c..531578a 100644
--- a/Makefile
+++ b/Makefile
@@ -2,8 +2,8 @@ make: trie $(wildcard src/*.c)
 	mkdir -p bin
 	gcc src/*.c -Wall -Wextra -pedantic -ggdb -o bin/sysh
 
-trie: triegen.py commands
-	python triegen.py commands src/trie.c
+trie: gen/triegen.py gen/commands
+	python gen/triegen.py gen/commands gen/syscalls_x86_64 src/trie.c
 
 clean: 
 	rm -f src/trie.c
diff --git a/examples/cat.sysh b/examples/cat.sysh
new file mode 100644
index 0000000..fb8db4c
--- /dev/null
+++ b/examples/cat.sysh
@@ -0,0 +1,5 @@
+.set $buf { .alloc 1024 }
+.set $read { read 0 $buf 1024 }
+write 1 $buf $read
+.free $buf
+
diff --git a/examples/helloworld.sysh b/examples/helloworld.sysh
new file mode 100644
index 0000000..0188033
--- /dev/null
+++ b/examples/helloworld.sysh
@@ -0,0 +1 @@
+write 1 "Hello, world!\n" 14
diff --git a/gen/commands b/gen/commands
new file mode 100644
index 0000000..927ae4a
--- /dev/null
+++ b/gen/commands
@@ -0,0 +1,10 @@
+.alloc          C_ALLOC
+.realloc        C_REALLOC
+.free           C_FREE
+.set            C_SET
+.cpy            C_CPY
+.deref          C_DEREF
+.strerror       C_STRERROR
+.if             C_IF
+.while          C_WHILE
+.for            C_FOR
diff --git a/commands b/gen/syscalls_x86_64
similarity index 100%
rename from commands
rename to gen/syscalls_x86_64
diff --git a/triegen.py b/gen/triegen.py
similarity index 86%
rename from triegen.py
rename to gen/triegen.py
index 40eb3a3..aa40a32 100755
--- a/triegen.py
+++ b/gen/triegen.py
@@ -9,17 +9,18 @@ if len(sys.argv) < 3:
     print("Not enough arguments. Usage: triegen.py <input> <output>")
     sys.exit(1)
 
-input_file = sys.argv[1]
-output_file = sys.argv[2]
+output_file = sys.argv[len(sys.argv) - 1]
 
-with open(input_file, 'r') as f:
-    data = [re.split('\s+', l.strip()) for l in f.read().split('\n') if len(l.strip()) > 0]
+data = []
+for input_file in sys.argv[1:-1]:
+    with open(input_file, 'r') as f:
+        data += [re.split('\s+', l.strip()) for l in f.read().split('\n') if len(l.strip()) > 0]
 
 trie = {}
 
 for line in data:
     key = line[0] + '\0'
-    val = int(line[1])
+    val = line[1]
     trie_local = trie
     for c in key:
         if c == '\0':
@@ -67,7 +68,7 @@ with open(output_file, 'w') as f:
     f.write("#include <string.h>\n")
     f.write("#include \"trie.h\"\n\n")
     f.write("/* auto-generated by triegen.py */\n\n")
-    f.write("int trie_get(const char* key) {\n  ")
+    f.write("long trie_get(const char* key) {\n  ")
     write_trie(f, trie, 0)
     f.write("  return -1;\n}\n")
             
diff --git a/src/eval.c b/src/eval.c
index 4fc3e73..4499f5d 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -3,34 +3,67 @@
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>
+#include <stdarg.h>
 
 #include "eval.h"
+#include "hashmap.h"
 #include "parser.h"
 #include "scanner.h"
+#include "trie.h"
 
-static long eval_syscall(Line* line) {
+#define LOGERROR(msg) fprintf(stderr, "sysh: " msg ## "\n")
+
+static void log_error(const char* format, ...) {
+    va_list args;
+    va_start(args, format);
+    fprintf(stderr, "sysh: ");
+    vfprintf(stderr, format, args);
+    fprintf(stderr, "\n");
+}
+
+bool eval_arg(Argument arg, long* result, bool* cloned, Hashmap* vars) {
+    if(arg.type == ARG_NUM) {
+        *result = arg.as.num;
+        if(cloned) *cloned = false;
+        return true;
+    } else if(arg.type == ARG_STR && cloned != NULL) {
+        int len = strlen(arg.as.str);
+        char* buf = malloc(len + 1);
+        strcpy(buf, arg.as.str);
+        *result = (long)buf;
+        *cloned = true;
+        return true;
+    } else if(arg.type == ARG_BLOCK) {
+        *result = eval_block(&arg.as.block, vars);        
+        if(cloned) *cloned = false;
+        return true;
+    } else if(arg.type == ARG_VAR) {
+        if(hashmap_get(vars, arg.as.str, result)) {
+            if(cloned) *cloned = false;
+            return true;
+        } else {
+            return false;
+        }
+    } {
+        return false;
+    }
+}
+
+static long eval_syscall(Line* line, Hashmap* vars) {
     if(line->len > 6) {
-        fprintf(stderr, "sysh: too many args for syscall\n");
-        return 0;
+        log_error("too many arguments for syscall: got %d", line->len);
+        return -1;
     }
     long args[6] = {0,0,0,0,0,0};
     bool cloned[6] = {0,0,0,0,0,0};
     for(int i = 0; i < line->len; i++) {
         Argument arg = line->args[i];
-        if(arg.type == ARG_NUM) {
-            args[i] = arg.as.num;
-        } else if(arg.type == ARG_STR) {
-            int len = strlen(arg.as.str);
-            char* buf = malloc(len + 1);
-            strcpy(buf, arg.as.str);
-            args[i] = (long)buf;
-            cloned[i] = true;
-        } else {
+        if(!eval_arg(arg, &args[i], &cloned[i], vars)) {
             for(int j = 0; j < line->len; j++) {
                 if(cloned[j]) free((void*)args[j]);
             }
-            fprintf(stderr, "sysh: invalid arg type\n");
-            return 0;
+            log_error("bad argument to syscall");
+            return -1;
         }
     }
     long result = syscall(line->id, args[0], args[1], args[2], args[3], args[4], args[5]);
@@ -40,24 +73,93 @@ static long eval_syscall(Line* line) {
     return result;
 }
 
-static long eval_line(Line* line) {
-    if(line->id >= 0) {
-        return eval_syscall(line);
+static long eval_alloc(Line* line, Hashmap* vars) {
+    if(line->len != 1) {
+        log_error(".alloc expected 1 arg, got %d", line->len);
+        return -1;
+    }
+    long val;
+    if(!eval_arg(line->args[0], &val, NULL, vars)) {
+        log_error("bad argument to .alloc");
+        return -1;
+    }
+    return (long)malloc(val);
+}
+
+static long eval_realloc(Line* line, Hashmap* vars) {
+    if(line->len != 2) {
+        log_error(".realloc expected 2 args, got %d", line->len);
+        return -1;
+    }
+    long val1;
+    long val2;
+    if(!eval_arg(line->args[0], &val1, NULL, vars)) {
+        log_error("bad argument to .realloc");
+        return -1;
+    }
+    if(!eval_arg(line->args[1], &val2, NULL, vars)) {
+        log_error("bad argument to .realloc");
+        return -1;
+    }
+    return (long)realloc((void*)val1, val2);
+}
+
+static long eval_free(Line* line, Hashmap* vars) {
+    if(line->len != 1) {
+        log_error(".free expected 1 args, got %d", line->len);
+        return -1;
+    }
+    long val;
+    if(!eval_arg(line->args[0], &val, NULL, vars)) {
+        log_error("bad argument to .free");
+        return -1;
+    }
+    free((void*)val);
+    return 0;
+}
+
+static long eval_set(Line* line, Hashmap* vars) {
+    if(line->len < 0 || line->len > 2) {
+        log_error(".set expected 1 or 2 args, got %d", line->len);
+        return -1;
+    }
+    if(line->args[0].type != ARG_VAR) {
+        log_error("bad argument to .set");
+        return -1;
+    }
+    if(line->len == 2) {
+        long val;
+        bool cloned;
+        if(!eval_arg(line->args[1], &val, &cloned, vars)) {
+            log_error("bad argument to .set");
+            return -1;
+        }
+        hashmap_add(vars, strdup(line->args[0].as.str), val);
     } else {
-        // TODO
-        return 0;
+        hashmap_remove(vars, line->args[0].as.str);
+    }
+    return 0;
+}
+
+static long eval_line(Line* line, Hashmap* vars) {
+    if(line->id >= 0) {
+        return eval_syscall(line, vars);
+    } else switch(line->id) {
+        case C_ALLOC:   return eval_alloc(line, vars);
+        case C_REALLOC: return eval_realloc(line, vars);
+        case C_FREE:    return eval_free(line, vars);
+        case C_SET:     return eval_set(line, vars);
+        default: return 0; // unreachable
     }
 }
 
-
-long eval_block(Block* block) {
+long eval_block(Block* block, Hashmap* vars) {
     long result = 0;
     for(int i = 0; i < block->len; i++) {
-        result = eval_line(&block->lines[i]);
+        result = eval_line(&block->lines[i], vars);
         if(errno > 0) {
             fprintf(stderr, "E%d: %s\n", errno, strerror(errno));
         } 
-        break;
     }
     return result;
 }
diff --git a/src/eval.h b/src/eval.h
index ea2bfa1..b07950e 100644
--- a/src/eval.h
+++ b/src/eval.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include "hashmap.h"
 #include "parser.h"
 
-long eval_block(Block* block);
+long eval_block(Block* block, Hashmap* vars);
diff --git a/src/hashmap.c b/src/hashmap.c
new file mode 100644
index 0000000..4f6799a
--- /dev/null
+++ b/src/hashmap.c
@@ -0,0 +1,107 @@
+#include <stdint.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include "hashmap.h"
+
+static uint32_t hash_string(const char* key) {
+    uint32_t hash = 2166136261u;
+    while(*key != '\0') {
+        hash ^= (uint8_t)(*key);
+        hash *= 16777619;
+        key++;
+    }
+    return hash;
+}
+
+void hashmap_init(Hashmap* hashmap) {
+    hashmap->len = 0;
+    hashmap->capacity = 0;
+    hashmap->entries = NULL;
+}
+
+void hashmap_free(Hashmap* hashmap) {
+    for(int i = 0; i < hashmap->capacity; i++) {
+        Entry e = hashmap->entries[i];
+        if(e.key != NULL) free((char*)e.key);
+    }
+    free(hashmap->entries);
+    hashmap_init(hashmap);
+}
+
+static Entry* hashmap_find(Entry* entries, int capacity, const char* key) {
+    uint32_t index = hash_string(key) % capacity;
+    Entry* tombstone = NULL;
+    while(true) {
+        Entry* entry = &entries[index];
+        if(entry->key == NULL) {
+            if(entry->value == 1) {
+                if(tombstone == NULL) tombstone = entry;
+            } else {
+                return (tombstone == NULL) ? entry : tombstone;
+            }
+        } else if(strcmp(entry->key, key) == 0) {
+            return entry;
+        }
+    }
+}
+
+static void hashmap_grow(Hashmap* map, int capacity) {
+    Entry* entries = malloc(capacity * sizeof(Entry));
+    for(int i = 0; i < capacity; i++) {
+        entries[i].key = NULL;
+        entries[i].value = 0;
+    }
+    map->len = 0;
+    for(int i = 0; i < map->capacity; i++) {
+        Entry* entry = &map->entries[i];
+        if(entry->key == NULL) continue;
+        
+        Entry* dest = hashmap_find(entries, capacity, entry->key);
+        dest->key = entry->key;
+        dest->value = entry->value;
+        map->len++;
+    }
+    free(map->entries);
+
+    map->entries = entries;
+    map->capacity = capacity;
+}
+
+bool hashmap_get(Hashmap* hashmap, const char* key, long* value) {
+    if(hashmap->len == 0) return false;
+
+    Entry* e = hashmap_find(hashmap->entries, hashmap->capacity, key);
+    if(e->key == NULL) return false;
+
+    *value = e->value;
+    return true;
+}
+
+bool hashmap_add(Hashmap* hashmap, char* key, long value) {
+    if(hashmap->len + 1 > hashmap->capacity * TABLE_MAX_LOAD) {
+        int capacity = (hashmap->capacity == 0 ? 8 : (2 * hashmap->capacity));
+        hashmap_grow(hashmap, capacity);
+    }
+    Entry* e = hashmap_find(hashmap->entries, hashmap->capacity, key);
+    bool new_key = e->key == NULL;
+    if(new_key) {
+        hashmap->len++;
+    }
+    e->key = key;
+    e->value = value;                
+    return new_key;
+}
+
+bool hashmap_remove(Hashmap* hashmap, const char* key) {
+    if(hashmap->len == 0) return false;
+
+    Entry* e = hashmap_find(hashmap->entries, hashmap->capacity, key);
+    if(e->key == NULL) return false;
+
+    e->key = NULL;
+    e->value = 1;
+    return true;
+}
diff --git a/src/hashmap.h b/src/hashmap.h
new file mode 100644
index 0000000..d0f94a4
--- /dev/null
+++ b/src/hashmap.h
@@ -0,0 +1,23 @@
+#pragma once
+#include <stdbool.h>
+
+#define TABLE_MAX_LOAD 0.75
+
+typedef struct {
+    const char* key;
+    long value;
+} Entry;
+
+typedef struct {
+    int len;
+    int capacity;
+    Entry* entries;
+} Hashmap;
+
+void hashmap_init(Hashmap* hashmap);
+void hashmap_free(Hashmap* hashmap);
+
+bool hashmap_add(Hashmap* hashmap, char* key, long value);
+bool hashmap_get(Hashmap* hashmap, const char* key, long* value);
+bool hashmap_remove(Hashmap* hashmap, const char* key);
+
diff --git a/src/main.c b/src/main.c
index d93a12b..f2ec596 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,9 +1,12 @@
+#include <errno.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <assert.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "eval.h"
+#include "hashmap.h"
 #include "parser.h"
 #include "scanner.h"
 
@@ -11,9 +14,11 @@
 #define PROMPT "[%ld]sysh$ "
 #define EPROMPT "[E]sysh$ "
 
-void repl() {
+static long repl() {
     char buf[LINE_LEN];
     printf(PROMPT, 0L);
+    Hashmap vars;
+    hashmap_init(&vars);
     while(fgets(buf, LINE_LEN, stdin)) {
         Scanner sc = init_scanner(buf);
         BlockResult br = parse(&sc);
@@ -21,14 +26,51 @@ void repl() {
             printf("sysh: %s\n", br.as.err);
             printf(EPROMPT);
         } else if(br.as.ok.len > 0) {
-            long result = eval_block(&br.as.ok);
+            long result = eval_block(&br.as.ok, &vars);
             printf(PROMPT, result);
             block_free(&br.as.ok);
         }
     }
-}
-
-int main(void) {
-    repl();
+    hashmap_free(&vars);
     return 0;
 }
+
+static long run_file(const char* name) {
+    FILE* file = fopen(name, "r");
+    if(file == NULL) {
+        fprintf(stderr, "%s\n", strerror(errno));
+        return 1;
+    }
+    fseek(file, 0, SEEK_END);
+    long fsize = ftell(file);
+    fseek(file, 0, SEEK_SET);
+
+    char* buf = malloc(fsize + 1);
+    fread(buf, fsize, 1, file);
+    fclose(file);
+
+    buf[fsize] = '\0';
+
+    Hashmap vars;
+    hashmap_init(&vars);
+    Scanner sc = init_scanner(buf);
+    BlockResult br = parse(&sc);
+    if(!br.is_ok) {
+        printf("sysh: %s\n", br.as.err);
+    } else if(br.as.ok.len > 0) {
+        eval_block(&br.as.ok, &vars);
+        block_free(&br.as.ok);
+    }
+    hashmap_free(&vars);
+    free(buf);
+
+    return 0;
+}
+
+int main(int argc, const char** argv) {
+    if(argc < 1) return 1;
+    if(argc == 1) return repl();
+    if(argc == 2) return run_file(argv[1]);
+    fprintf(stderr, "usage: %s [file]\n", argv[0]);
+    return 1;
+}
diff --git a/src/parser.c b/src/parser.c
index 88f7527..012b0f7 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -65,8 +65,9 @@ void line_free(Line* line) {
     free(line->args);
 }
 
+static BlockResult parse_block(Scanner* sc, bool braced);
 
-static LineResult parse_line(Scanner* sc, int id) {
+static LineResult parse_line(Scanner* sc, int id, bool* brace_end) {
     Line line;
     line_init(&line, id);
     while(true) {
@@ -74,6 +75,10 @@ static LineResult parse_line(Scanner* sc, int id) {
         switch(tok.type) {
             case TOK_EOF:
             case TOK_EOL:
+                *brace_end = false;
+                return OK(line, LineResult);
+            case TOK_RBRACE:
+                *brace_end = true;
                 return OK(line, LineResult);
             case TOK_ERR: 
                 line_free(&line);
@@ -90,9 +95,17 @@ static LineResult parse_line(Scanner* sc, int id) {
             case TOK_CMD:
                 line_add(&line, (Argument){.type = ARG_CMD, .as.str = tok.as.str});
                 break;
+            case TOK_LBRACE: {
+                BlockResult br = parse_block(sc, true);
+                if(!br.is_ok) {
+                    line_free(&line);
+                    return ERR(br.as.err, LineResult);
+                }
+                line_add(&line, (Argument){.type = ARG_BLOCK, .as.block = br.as.ok});
+            } break;
             default:
                 line_free(&line);
-                return ERR("unexpected token", LineResult);
+                return ERR("unexpected token in line: %d", LineResult);
         }
     }
 }
@@ -118,16 +131,25 @@ static BlockResult parse_block(Scanner* sc, bool braced)  {
                     block_free(&block);
                     return ERR("invalid syscall or command name", BlockResult);
                 }
-                LineResult sr = parse_line(sc, id);
+                bool brace_end;
+                LineResult sr = parse_line(sc, id, &brace_end);
                 if(!sr.is_ok) {
                     block_free(&block);
                     return ERR(sr.as.err, BlockResult);
                 }
+                if(brace_end && !braced) {
+                    line_free(&sr.as.ok);
+                    block_free(&block);
+                    return ERR("unexpected token in block", BlockResult);
+                }
                 block_add(&block, sr.as.ok);
+                if(brace_end) {
+                    return OK(block, BlockResult);
+                }
             } break;
             default: 
                 block_free(&block);
-                return ERR("unexpected token", BlockResult);
+                return ERR("unexpected token in block", BlockResult);
         }
     }
     return OK(block, BlockResult);
diff --git a/src/trie.h b/src/trie.h
index 46fcd3b..a1f7c9f 100644
--- a/src/trie.h
+++ b/src/trie.h
@@ -1,3 +1,14 @@
 #pragma once
 
-int trie_get(const char* key);
+#define C_ALLOC     -2
+#define C_REALLOC   -3
+#define C_FREE      -4
+#define C_SET       -5
+#define C_CPY       -6
+#define C_DEREF     -7
+#define C_STRERROR  -8
+#define C_IF        -9
+#define C_WHILE     -10
+#define C_FOR       -11
+
+long trie_get(const char* key);