diff --git a/.gitignore b/.gitignore
index 1ab7e1e..b626445 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,10 @@
 kr
+*.bak
+*.exe
 *.o
 *.profraw
 *.profdata
+*~
 tmp
 test.out
 cov
diff --git a/README.md b/README.md
index ba5fcf6..aee9fa0 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ AEAD interface of Monocypher to encrypt/decrypt files using
 `kr` offers two modes of operation:
 
 - Keyfile-based: a private key is stored on the user's machine and is used to
-  encrypt and decrypt files. 
+  encrypt and decrypt files.
 
 - Passphrase-based: an encryption/decryption key is generated, on the fly, using
   Argon2i (with a random salt).
@@ -65,7 +65,7 @@ _same_ pair (passphrase, userID) on every invocation. For example:
 ```
 $ kr -guUSERID -p"PASS PHRASE" ~/key.sec
 ```
- Or 
+ Or
 
 ```
 $ kr -g --uid=USERID --passphrase="PASS PHRASE" ~/key.sec
@@ -173,7 +173,7 @@ pipes:
 ```
 $ echo 'Hello, world!' | kr -epPASS | kr -dpPASS
 ```
-or with keyfiles 
+or with keyfiles
 
 ```
 $ echo 'Hello, world!' | kr -ek ~/.key.sec | kr -dk ~/.key.sec
diff --git a/src/kr.c b/src/kr.c
index 8e070a4..55ca803 100644
--- a/src/kr.c
+++ b/src/kr.c
@@ -264,7 +264,7 @@ static enum error encrypt(FILE *in, FILE *out, const uint8_t key[KEY_SIZE],
         uint8_t *ad = (eof) ? END_TAG : NULL; // if last chunk, tag it.
         size_t adlen = (eof) ? 4 : 0;
 
-        // Arguments order: 
+        // Arguments order:
         // ctx, cipher_text, mac, ad, ad_size, plain_text, text_size.
         // The mac comes after the encrypted chunk, thus:
         // - the mac is located at buf_out + len, and
@@ -318,7 +318,7 @@ static enum error decrypt(FILE *in, FILE *out, const uint8_t key[KEY_SIZE],
         uint8_t *ad = (eof) ? END_TAG : 0; // last chunk should've been tagged.
         size_t adlen = (eof) ? 4 : 0;
 
-        // Arguments order: 
+        // Arguments order:
         // ctx, plain_text, mac, ad, ad_size, cipher_text, text_size.
         // The read 'len' bytes from 'in' already includes the mac, thus:
         // - the mac is located at buf_in + len - MAC_SIZE, and
@@ -343,7 +343,7 @@ static enum error decrypt(FILE *in, FILE *out, const uint8_t key[KEY_SIZE],
 }
 
 // Generate a key_size bytes key from a passphrase and a salt (random)
-// using Argon2i (with configuration in 'config', inputs (password and salt) 
+// using Argon2i (with configuration in 'config', inputs (password and salt)
 // data in 'inputs'), and extras (key and ad). This needs a work area that
 // has to be allocated. If this allocation fails, securely wipe inputs and
 // extras and exit.
@@ -448,7 +448,7 @@ static enum error read_keyfile(FILE *kf, uint8_t key[KEY_SIZE])
     // Inspect the protection-version byte, and get its MSB.
     int protected = *version >> 7;
     if (!protected) {
-        // Key is not protected. Copy the last KEY_SIZE bytes. 
+        // Key is not protected. Copy the last KEY_SIZE bytes.
         memcpy(key, fkey, KEY_SIZE);
     } else {
         // Ask the user to provide a passphrase to decrypt the key.
@@ -709,7 +709,7 @@ int main(int argc, char *argv[])
     // outfile is needed for encryption, decryption, and keygen.
     if (mode & (MODE_ENCRYPT | MODE_DECRYPT | MODE_KEYGEN)) {
         outfile =  optparse_arg(&options);
-        out = !outfile ? stdout : fopen(outfile, "wb");
+        out = !outfile || !strcmp(outfile, "-") ? stdout : fopen(outfile, "wb");
         if (!out) {
             BAIL(ERR_OUTPUT_FILE);
         }
@@ -722,7 +722,7 @@ int main(int argc, char *argv[])
                 BAIL(ERR_NO_RANDOM);
             }
             // If the key to be generated depends on a uid and a passphrase,
-            // generate a deterministic one with the same value when given 
+            // generate a deterministic one with the same value when given
             // the same uid and passphrase.
             if (use_passphrase) {
                 // Hash the uid to use it as a salt for key derivation.
@@ -830,7 +830,7 @@ int main(int argc, char *argv[])
     }
 
 // Clean everything and exit.
-bail: 
+bail:
     // Safely wipe sensitive info.
     crypto_wipe(key, KEY_SIZE);
     crypto_wipe(passphrase, MAXPASS);
diff --git a/tests/tests.c b/tests/tests.c
index e1df47a..b4a33e2 100644
--- a/tests/tests.c
+++ b/tests/tests.c
@@ -266,7 +266,7 @@ static int p_encrypt_decrypt(void)
             fsize = 0;
         }
         if (DEBUG) {
-            printf(YELLOW "\tFile size:" BLUE " %lu bytes\n", fsize);
+            printf(YELLOW "\tFile size:" BLUE " %" PRIu64 " bytes\n", fsize);
         }
         fillrand(data, fsize);
         fillrand(key, KEY_SIZE);
@@ -428,7 +428,7 @@ int p_password_enc_dec(void)
         }
 
         if (DEBUG) {
-            printf(YELLOW "\tFile size:" BLUE " %lu bytes\n", fsize);
+            printf(YELLOW "\tFile size:" BLUE " %" PRIu64 " bytes\n", fsize);
         }
 
         fillrand(data, fsize);