diff --git a/Cargo.lock b/Cargo.lock
index 5cc44ab63..f18a2b052 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -119,7 +119,7 @@ dependencies = [
 
 [[package]]
 name = "blake3"
-version = "0.3.3"
+version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "arrayref 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -293,10 +293,10 @@ version = "0.2.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro-error 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustversion 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -314,9 +314,9 @@ name = "failure_derive"
 version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -620,10 +620,10 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro-error-attr 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
- "version_check 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
+ "version_check 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -631,16 +631,16 @@ name = "proc-macro-error-attr"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "syn-mid 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "version_check 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "version_check 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.13"
+version = "1.0.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -660,7 +660,7 @@ name = "quote"
 version = "1.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -768,14 +768,15 @@ dependencies = [
 name = "redox_cookbook"
 version = "0.1.0"
 dependencies = [
- "blake3 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "blake3 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "pbr 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "pkgar 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "redoxer 0.2.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.110 (registry+https://github.com/rust-lang/crates.io-index)",
- "sha2 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sha2 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "termion 1.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "walkdir 2.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -826,7 +827,7 @@ dependencies = [
  "serde 1.0.110 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.110 (registry+https://github.com/rust-lang/crates.io-index)",
  "sha3 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "tar 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tar 0.4.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "version-compare 0.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -949,9 +950,9 @@ name = "rustversion"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -959,6 +960,14 @@ name = "safemem"
 version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "same-file"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi-util 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "scopeguard"
 version = "1.1.0"
@@ -986,14 +995,14 @@ name = "serde_derive"
 version = "1.0.110"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "sha2"
-version = "0.8.1"
+version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "block-buffer 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1039,10 +1048,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "syn"
-version = "1.0.23"
+version = "1.0.25"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1052,9 +1061,9 @@ name = "syn-mid"
 version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1062,9 +1071,9 @@ name = "synstructure"
 version = "0.12.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1075,7 +1084,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "tar"
-version = "0.4.27"
+version = "0.4.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "filetime 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1235,9 +1244,19 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "version_check"
-version = "0.9.1"
+version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "walkdir"
+version = "2.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "same-file 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi-util 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "wasi"
 version = "0.9.0+wasi-snapshot-preview1"
@@ -1275,6 +1294,14 @@ name = "winapi-i686-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
@@ -1305,7 +1332,7 @@ dependencies = [
 "checksum bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 "checksum blake2b_simd 0.5.10 (registry+https://github.com/rust-lang/crates.io-index)" = "d8fb2d74254a3a0b5cac33ac9f8ed0e44aa50378d9dbb2e5d83bd21ed1dc2c8a"
 "checksum blake3 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "667d945f23cefed0b5f973af35c4bc3319caa6776fbda270e4897d8504afa8e4"
-"checksum blake3 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "68df31bdf2bbb567e5adf8f21ac125dc0e897b1381e7b841f181521f06fc3134"
+"checksum blake3 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "423897d97e11b810c9da22458400b28ec866991c711409073662eb34dc44bfff"
 "checksum block-buffer 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)" = "c0940dc441f31689269e10ac70eb1002a3a1d3ad1390e030043662eb7fe4688b"
 "checksum block-padding 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "fa79dedbb091f449f1f39e53edf88d5dbe95f895dae6135a8d7b881fb5af73f5"
 "checksum byte-tools 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "e3b5ca7a04898ad4bcd41c90c5285445ff5b791899bb1b0abdd2a2aa791211d7"
@@ -1370,7 +1397,7 @@ dependencies = [
 "checksum ppv-lite86 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "237a5ed80e274dbc66f86bd59c1e25edc039660be53194b5fe0a482e0f2612ea"
 "checksum proc-macro-error 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "98e9e4b82e0ef281812565ea4751049f1bdcdfccda7d3f459f2e138a40c08678"
 "checksum proc-macro-error-attr 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "4f5444ead4e9935abd7f27dc51f7e852a0569ac888096d5ec2499470794e2e53"
-"checksum proc-macro2 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)" = "53f5ffe53a6b28e37c9c1ce74893477864d64f74778a93a4beb43c8fa167f639"
+"checksum proc-macro2 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)" = "1502d12e458c49a4c9cbff560d0fe0060c252bc29799ed94ca2ed4bb665a0101"
 "checksum proc-mounts 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "2ad7e9c8d1b8c20f16a84d61d7c4c0325a5837c1307a2491b509cd92fb4e4442"
 "checksum quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "54a21852a652ad6f610c9510194f398ff6f8692e334fd1145fed931f7fbe44ea"
 "checksum rand 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)" = "64ac302d8f83c0c1974bf758f6b041c6c8ada916fbb44a609158ca8b064cc76c"
@@ -1401,21 +1428,22 @@ dependencies = [
 "checksum rustls 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)" = "942b71057b31981152970d57399c25f72e27a6ee0d207a669d8304cabf44705b"
 "checksum rustversion 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "b3bba175698996010c4f6dce5e7f173b6eb781fce25d2cfc45e27091ce0b79f6"
 "checksum safemem 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ef703b7cb59335eae2eb93ceb664c0eb7ea6bf567079d843e09420219668e072"
+"checksum same-file 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
 "checksum scopeguard 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 "checksum sct 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "cb8f61f9e6eadd062a71c380043d28036304a4706b3c4dd001ff3387ed00745a"
 "checksum serde 1.0.110 (registry+https://github.com/rust-lang/crates.io-index)" = "99e7b308464d16b56eba9964e4972a3eee817760ab60d88c3f86e1fecb08204c"
 "checksum serde_derive 1.0.110 (registry+https://github.com/rust-lang/crates.io-index)" = "818fbf6bfa9a42d3bfcaca148547aa00c7b915bec71d1757aa2d44ca68771984"
-"checksum sha2 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "27044adfd2e1f077f649f59deb9490d3941d674002f7d062870a60ebe9bd47a0"
+"checksum sha2 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a256f46ea78a0c0d9ff00077504903ac881a1dafdc20da66545699e7776b3e69"
 "checksum sha3 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)" = "dd26bc0e7a2e3a7c959bc494caf58b72ee0c71d67704e9520f736ca7e4853ecf"
 "checksum smallvec 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c7cb5678e1615754284ec264d9bb5b4c27d2018577fd90ac0ceb578591ed5ee4"
 "checksum sodalite 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "67643084c740297bac275b1d97901ec27ca5984be4e8f75d86a33498e0e3e61c"
 "checksum strsim 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
 "checksum subtle 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2d67a5a62ba6e01cb2192ff309324cb4875d0c451d55fe2319433abe7a05a8ee"
-"checksum syn 1.0.23 (registry+https://github.com/rust-lang/crates.io-index)" = "95b5f192649e48a5302a13f2feb224df883b98933222369e4b3b0fe2a5447269"
+"checksum syn 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)" = "f14a640819f79b72a710c0be059dce779f9339ae046c8bef12c361d56702146f"
 "checksum syn-mid 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7be3539f6c128a931cf19dcee741c1af532c7fd387baa739c03dd2e96479338a"
 "checksum synstructure 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)" = "67656ea1dc1b41b1451851562ea232ec2e5a80242139f7e679ceccfb5d61f545"
 "checksum take_mut 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f764005d11ee5f36500a149ace24e00e3da98b0158b3e2d53a7495660d3f4d60"
-"checksum tar 0.4.27 (registry+https://github.com/rust-lang/crates.io-index)" = "7160add8f178ecef9c22e9d8f8ed28bc9a39660e98b1c28d93cc026ad9619f09"
+"checksum tar 0.4.28 (registry+https://github.com/rust-lang/crates.io-index)" = "5c058ad0bd6ccb84faa24cc44d4fc99bee8a5d7ba9ff33aa4d993122d1aeeac2"
 "checksum tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e24d9338a0a5be79593e2fa15a648add6138caa803e2d5bc782c371732ca9"
 "checksum termion 1.5.5 (registry+https://github.com/rust-lang/crates.io-index)" = "c22cec9d8978d906be5ac94bceb5a010d885c626c4c8855721a4dbd20e3ac905"
 "checksum textwrap 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
@@ -1437,11 +1465,13 @@ dependencies = [
 "checksum vec_map 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f1bddf1187be692e79c5ffeab891132dfb0f236ed36a43c7ed39f1165ee20191"
 "checksum version-compare 0.0.10 (registry+https://github.com/rust-lang/crates.io-index)" = "d63556a25bae6ea31b52e640d7c41d1ab27faba4ccb600013837a3d0b3994ca1"
 "checksum version_check 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "914b1a6776c4c929a602fafd8bc742e06365d4bcbe48c30f9cca5824f70dc9dd"
-"checksum version_check 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)" = "078775d0255232fb988e6fccf26ddc9d1ac274299aaedcedce21c6f72cc533ce"
+"checksum version_check 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)" = "b5a972e5669d67ba988ce3dc826706fb0a8b01471c088cb0b6110b805cc36aed"
+"checksum walkdir 2.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "777182bc735b6424e1a57516d35ed72cb8019d85c8c9bf536dccb3445c1a2f7d"
 "checksum wasi 0.9.0+wasi-snapshot-preview1 (registry+https://github.com/rust-lang/crates.io-index)" = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
 "checksum webpki 0.18.1 (registry+https://github.com/rust-lang/crates.io-index)" = "17d7967316d8411ca3b01821ee6c332bde138ba4363becdb492f12e514daa17f"
 "checksum webpki-roots 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)" = "85d1f408918fd590908a70d36b7ac388db2edc221470333e4d6e5b598e44cabf"
 "checksum winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+"checksum winapi-util 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 "checksum xattr 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "244c3741f4240ef46274860397c7c74e50eb23624996930e484c16679633a54c"
diff --git a/Cargo.toml b/Cargo.toml
index a6d2a37a3..3d118d197 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,11 +20,12 @@ name = "cookbook"
 path = "src/lib.rs"
 
 [dependencies]
-blake3 = "0.3.3"
+blake3 = "0.3.4"
 pbr = "1.0.2"
 pkgar = "0.1.6"
 redoxer = "0.2.19"
-serde = { version = "1.0", features = ["derive"] }
-sha2 = "0.8.1"
+serde = { version = "1.0.110", features = ["derive"] }
+sha2 = "0.8.2"
 termion = "1.5.5"
 toml = "0.5.6"
+walkdir = "2.3.1"
diff --git a/src/bin/cook.rs b/src/bin/cook.rs
index 4f0584378..ceda38095 100644
--- a/src/bin/cook.rs
+++ b/src/bin/cook.rs
@@ -4,25 +4,73 @@ use cookbook::sha256::sha256_progress;
 use std::{
     env,
     fs,
-    io::Write,
+    io::{self, Write},
     path::{Path, PathBuf},
     process::{self, Command, Stdio},
+    time::SystemTime,
 };
 use termion::{color, style};
+use walkdir::WalkDir;
+
+fn remove_all(path: &Path) -> Result<(), String> {
+    if path.is_dir() {
+        fs::remove_dir_all(path)
+    } else {
+        fs::remove_file(path)
+    }.map_err(|err| format!(
+        "failed to remove '{}': {}\n{:?}",
+        path.display(),
+        err,
+        err
+    ))
+}
+
+fn create_dir(dir: &Path) -> Result<(), String> {
+    fs::create_dir(&dir).map_err(|err| format!(
+        "failed to create '{}': {}\n{:?}",
+        dir.display(),
+        err,
+        err
+    ))
+}
 
 fn create_dir_clean(dir: &Path) -> Result<(), String> {
     if dir.is_dir() {
-        // Remove previous directory
-        fs::remove_dir_all(&dir).map_err(|err| format!(
-            "failed to remove '{}': {}\n{:?}",
-            dir.display(),
-            err,
-            err
-        ))?;
+        remove_all(dir)?;
     }
-    // directory
-    fs::create_dir(&dir).map_err(|err| format!(
-        "failed to create '{}': {}\n{:?}",
+    create_dir(dir)
+}
+
+fn modified(path: &Path) -> Result<SystemTime, String> {
+    let metadata = fs::metadata(path).map_err(|err| format!(
+        "failed to get metadata of '{}': {}\n{:#?}",
+        path.display(),
+        err,
+        err
+    ))?;
+    metadata.modified().map_err(|err| format!(
+        "failed to get modified time of '{}': {}\n{:#?}",
+        path.display(),
+        err,
+        err
+    ))
+}
+
+fn modified_dir(dir: &Path) -> Result<SystemTime, String> {
+    fn modified_dir_io(dir: &Path) -> io::Result<SystemTime> {
+        let mut newest = fs::metadata(dir)?.modified()?;
+        for entry_res in WalkDir::new(dir) {
+            let entry = entry_res?;
+            let modified = entry.metadata()?.modified()?;
+            if modified > newest {
+                newest = modified;
+            }
+        }
+        Ok(newest)
+    }
+
+    modified_dir_io(&dir).map_err(|err| format!(
+        "failed to get modified time of '{}': {}\n{:#?}",
         dir.display(),
         err,
         err
@@ -104,6 +152,7 @@ fn fetch(recipe_dir: &Path, source: &SourceRecipe) -> Result<PathBuf, String> {
     let source_dir = recipe_dir.join("source");
     match source {
         SourceRecipe::Git { git, upstream, branch, rev } => {
+            //TODO: use libgit?
             if ! source_dir.is_dir() {
                 // Create source.tmp
                 let source_dir_tmp = recipe_dir.join("source.tmp");
@@ -190,16 +239,14 @@ fn fetch(recipe_dir: &Path, source: &SourceRecipe) -> Result<PathBuf, String> {
                     rename(&source_tar_tmp, &source_tar)?;
                 }
 
+                // Calculate blake3
+                let source_tar_blake3 = blake3_progress(&source_tar).map_err(|err| format!(
+                    "failed to calculate blake3 of '{}': {}\n{:?}",
+                    source_tar.display(),
+                    err,
+                    err
+                ))?;
                 if let Some(blake3) = blake3 {
-                    //TODO
-                    // Calculate blake3
-                    let source_tar_blake3 = blake3_progress(&source_tar).map_err(|err| format!(
-                        "failed to calculate blake3 of '{}': {}\n{:?}",
-                        source_tar.display(),
-                        err,
-                        err
-                    ))?;
-
                     // Check if it matches recipe
                     if &source_tar_blake3 != blake3 {
                         return Err(format!(
@@ -208,8 +255,16 @@ fn fetch(recipe_dir: &Path, source: &SourceRecipe) -> Result<PathBuf, String> {
                             blake3
                         ));
                     }
+                } else {
+                    //TODO: set blake3 hash on the recipe with something like "cook fix"
+                    eprintln!(
+                        "WARNING: set blake3 for '{}' to '{}'",
+                        source_tar.display(),
+                        source_tar_blake3
+                    );
                 }
 
+                //TODO: if blake3 is set, remove sha256
                 if let Some(sha256) = sha256 {
                     // Calculate sha256
                     let source_tar_sha256 = sha256_progress(&source_tar).map_err(|err| format!(
@@ -284,26 +339,25 @@ fn fetch(recipe_dir: &Path, source: &SourceRecipe) -> Result<PathBuf, String> {
 }
 
 fn build(recipe_dir: &Path, source_dir: &Path, build: &BuildRecipe) -> Result<PathBuf, String> {
+    let source_modified = modified_dir(&source_dir)?;
+
     let sysroot_dir = recipe_dir.join("sysroot");
+    // Rebuild sysroot if source is newer
+    //TODO: rebuild on recipe changes
+    if sysroot_dir.is_dir() {
+        if modified_dir(&sysroot_dir)? < source_modified {
+            remove_all(&sysroot_dir)?;
+        }
+    }
     if ! sysroot_dir.is_dir() {
         // Create sysroot.tmp
         let sysroot_dir_tmp = recipe_dir.join("sysroot.tmp");
         create_dir_clean(&sysroot_dir_tmp)?;
 
         // Make sure sysroot/include exists
-        fs::create_dir(sysroot_dir_tmp.join("include")).map_err(|err| format!(
-            "failed to create '{}/include': {}\n{:#?}",
-            sysroot_dir_tmp.display(),
-            err,
-            err
-        ))?;
+        create_dir(&sysroot_dir_tmp.join("include"))?;
         // Make sure sysroot/lib exists
-        fs::create_dir(sysroot_dir_tmp.join("lib")).map_err(|err| format!(
-            "failed to create '{}/lib': {}\n{:#?}",
-            sysroot_dir_tmp.display(),
-            err,
-            err
-        ))?;
+        create_dir(&sysroot_dir_tmp.join("lib"))?;
 
         for dependency in build.dependencies.iter() {
             let public_path = "build/public.key";
@@ -326,6 +380,13 @@ fn build(recipe_dir: &Path, source_dir: &Path, build: &BuildRecipe) -> Result<Pa
     }
 
     let stage_dir = recipe_dir.join("stage");
+    // Rebuild stage if source is newer
+    //TODO: rebuild on recipe changes
+    if stage_dir.is_dir() {
+        if modified_dir(&stage_dir)? < source_modified {
+            remove_all(&stage_dir)?;
+        }
+    }
     if ! stage_dir.is_dir() {
         // Create stage.tmp
         let stage_dir_tmp = recipe_dir.join("stage.tmp");
@@ -450,11 +511,7 @@ fn package(recipe_dir: &Path, stage_dir: &Path, package: &PackageRecipe) -> Resu
     let public_path = "build/public.key";
     if ! Path::new(secret_path).is_file() || ! Path::new(public_path).is_file() {
         if ! Path::new("build").is_dir() {
-            fs::create_dir("build").map_err(|err| format!(
-                "failed to create 'build': {}\n{:?}",
-                err,
-                err
-            ))?;
+            create_dir(Path::new("build"))?;
         }
         pkgar::bin::keygen(secret_path, public_path).map_err(|err| format!(
             "failed to generate pkgar keys: {:?}",
@@ -463,6 +520,14 @@ fn package(recipe_dir: &Path, stage_dir: &Path, package: &PackageRecipe) -> Resu
     }
 
     let package_file = recipe_dir.join("stage.pkgar");
+    // Rebuild package if stage is newer
+    //TODO: rebuild on recipe changes
+    if package_file.is_file() {
+        let stage_modified = modified_dir(&stage_dir)?;
+        if modified(&package_file)? < stage_modified {
+            remove_all(&package_file)?;
+        }
+    }
     if ! package_file.is_file() {
         pkgar::bin::create(
             secret_path,