diff --git a/src/command_fmt.cc b/src/command_fmt.cc
index 8803266a..cf31ea2a 100644
--- a/src/command_fmt.cc
+++ b/src/command_fmt.cc
@@ -2,8 +2,10 @@
 #include <sourcemeta/core/jsonschema.h>
 
 #include <fstream>  // std::ofstream
-#include <iostream> // std::cerr
+#include <iostream> // std::cerr, std::cout
 #include <sstream>  // std::ostringstream
+#include <utility>  // std::move
+#include <vector>   // std::vector
 
 #include "command.h"
 #include "error.h"
@@ -14,6 +16,9 @@
 
 auto sourcemeta::jsonschema::fmt(const sourcemeta::core::Options &options)
     -> void {
+  const bool output_json{options.contains("json")};
+  bool result{true};
+  std::vector<std::string> failed_files;
   const auto indentation{parse_indentation(options)};
   for (const auto &entry : for_each_json(options)) {
     if (entry.first.extension() == ".yaml" ||
@@ -51,13 +56,13 @@ auto sourcemeta::jsonschema::fmt(const sourcemeta::core::Options &options)
 
     if (options.contains("check")) {
       if (current.str() == expected.str()) {
-        LOG_VERBOSE(options) << "PASS: " << entry.first.string() << "\n";
+        LOG_VERBOSE(options) << "ok: " << entry.first.string() << "\n";
+      } else if (output_json) {
+        failed_files.push_back(entry.first.string());
+        result = false;
       } else {
-        std::cerr << "FAIL: " << entry.first.string() << "\n";
-        std::cerr << "Got:\n"
-                  << current.str() << "\nBut expected:\n"
-                  << expected.str() << "\n";
-        throw Fail{EXIT_FAILURE};
+        std::cerr << "fail: " << entry.first.string() << "\n";
+        result = false;
       }
     } else {
       if (current.str() != expected.str()) {
@@ -66,4 +71,31 @@ auto sourcemeta::jsonschema::fmt(const sourcemeta::core::Options &options)
       }
     }
   }
+
+  if (options.contains("check") && output_json) {
+    auto output_json_object{sourcemeta::core::JSON::make_object()};
+    output_json_object.assign("valid", sourcemeta::core::JSON{result});
+
+    if (!result) {
+      auto errors_array{sourcemeta::core::JSON::make_array()};
+      for (auto &file_path : failed_files) {
+        errors_array.push_back(sourcemeta::core::JSON{std::move(file_path)});
+      }
+
+      output_json_object.assign("errors", sourcemeta::core::JSON{errors_array});
+    }
+
+    sourcemeta::core::prettify(output_json_object, std::cout, indentation);
+    std::cout << "\n";
+  }
+
+  if (!result) {
+    if (!output_json) {
+      std::cerr << "\nRun the `fmt` command without `--check/-c` to fix the "
+                   "formatting"
+                << "\n";
+    }
+
+    throw Fail{EXIT_FAILURE};
+  }
 }
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index d4641188..57b221d1 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -37,7 +37,9 @@ add_jsonschema_test_unix(format/pass_multi_extension)
 add_jsonschema_test_unix(format/pass_yaml)
 add_jsonschema_test_unix(format/pass_check_yaml)
 add_jsonschema_test_unix(format/fail_check_single)
+add_jsonschema_test_unix(format/fail_check_many)
 add_jsonschema_test_unix(format/pass_check_single)
+add_jsonschema_test_unix(format/pass_check_single_verbose)
 add_jsonschema_test_unix(format/pass_check_single_keep_ordering)
 add_jsonschema_test_unix(format/pass_directory_ignore_directory)
 add_jsonschema_test_unix(format/pass_directory_ignore_file)
@@ -53,6 +55,10 @@ add_jsonschema_test_unix(format/pass_default_dialect)
 add_jsonschema_test_unix(format/pass_default_dialect_config)
 add_jsonschema_test_unix(format/pass_default_dialect_config_relative)
 add_jsonschema_test_unix(format/pass_bignum_real)
+add_jsonschema_test_unix(format/pass_check_single_json)
+add_jsonschema_test_unix(format/fail_check_single_json)
+add_jsonschema_test_unix(format/fail_check_many_json)
+add_jsonschema_test_unix(format/fail_check_single_json_indentation)
 
 # Validate
 add_jsonschema_test_unix(validate/fail_instance_enoent)
diff --git a/test/format/fail_check_many.sh b/test/format/fail_check_many.sh
new file mode 100755
index 00000000..b4825781
--- /dev/null
+++ b/test/format/fail_check_many.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+
+set -o errexit
+set -o nounset
+
+TMP="$(mktemp -d)"
+clean() { rm -rf "$TMP"; }
+trap clean EXIT
+
+mkdir "$TMP/schemas"
+
+cat << 'EOF' > "$TMP/schemas/1.json"
+{
+  "type": 1,
+  "$schema": "http://json-schema.org/draft-04/schema#"
+}
+EOF
+
+cat << 'EOF' > "$TMP/schemas/2.json"
+{
+  "type": 1,
+  "$schema": "http://json-schema.org/draft-04/schema#"
+}
+EOF
+
+cat << 'EOF' > "$TMP/schemas/3.json"
+{
+  "$schema": "http://json-schema.org/draft-04/schema#"
+}
+EOF
+
+"$1" fmt "$TMP/schemas" --check >"$TMP/output.txt" 2>&1 && CODE="$?" || CODE="$?"
+test "$CODE" = "1" || exit 1
+
+cat << EOF > "$TMP/expected.txt"
+fail: $(realpath "$TMP")/schemas/1.json
+fail: $(realpath "$TMP")/schemas/2.json
+
+Run the \`fmt\` command without \`--check/-c\` to fix the formatting
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected.txt"
diff --git a/test/format/fail_check_many_json.sh b/test/format/fail_check_many_json.sh
new file mode 100755
index 00000000..335bc427
--- /dev/null
+++ b/test/format/fail_check_many_json.sh
@@ -0,0 +1,45 @@
+#!/bin/sh
+
+set -o errexit
+set -o nounset
+
+TMP="$(mktemp -d)"
+clean() { rm -rf "$TMP"; }
+trap clean EXIT
+
+mkdir "$TMP/schemas"
+
+cat << 'EOF' > "$TMP/schemas/1.json"
+{
+  "type": 1,
+  "$schema": "http://json-schema.org/draft-04/schema#"
+}
+EOF
+
+cat << 'EOF' > "$TMP/schemas/2.json"
+{
+  "type": 1,
+  "$schema": "http://json-schema.org/draft-04/schema#"
+}
+EOF
+
+cat << 'EOF' > "$TMP/schemas/3.json"
+{
+  "$schema": "http://json-schema.org/draft-04/schema#"
+}
+EOF
+
+"$1" fmt "$TMP/schemas" --check --json >"$TMP/output.json" 2>&1 && CODE="$?" || CODE="$?"
+test "$CODE" = "1" || exit 1
+
+cat << EOF > "$TMP/expected.json"
+{
+  "valid": false,
+  "errors": [
+    "$(realpath "$TMP")/schemas/1.json",
+    "$(realpath "$TMP")/schemas/2.json"
+  ]
+}
+EOF
+
+diff "$TMP/output.json" "$TMP/expected.json"
diff --git a/test/format/fail_check_single.sh b/test/format/fail_check_single.sh
index 229bbebb..ff5440fc 100755
--- a/test/format/fail_check_single.sh
+++ b/test/format/fail_check_single.sh
@@ -14,26 +14,16 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json" --check 2>"$TMP/stderr.txt" && CODE="$?" || CODE="$?"
+"$1" fmt "$TMP/schema.json" --check >"$TMP/output.txt" 2>&1 && CODE="$?" || CODE="$?"
 test "$CODE" = "1" || exit 1
 
-cat << EOF > "$TMP/error.txt"
-FAIL: $(realpath "$TMP")/schema.json
-Got:
-{
-  "type": 1,
-  "\$schema": "http://json-schema.org/draft-04/schema#"
-}
-
-But expected:
-{
-  "\$schema": "http://json-schema.org/draft-04/schema#",
-  "type": 1
-}
+cat << EOF > "$TMP/expected.txt"
+fail: $(realpath "$TMP")/schema.json
 
+Run the \`fmt\` command without \`--check/-c\` to fix the formatting
 EOF
 
-diff "$TMP/stderr.txt" "$TMP/error.txt"
+diff "$TMP/output.txt" "$TMP/expected.txt"
 
 cat << 'EOF' > "$TMP/expected.json"
 {
diff --git a/test/format/fail_check_single_indentation.sh b/test/format/fail_check_single_indentation.sh
index 502e73ef..bf7578df 100755
--- a/test/format/fail_check_single_indentation.sh
+++ b/test/format/fail_check_single_indentation.sh
@@ -14,26 +14,16 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json" --indentation 4 --check 2>"$TMP/stderr.txt" && CODE="$?" || CODE="$?"
+"$1" fmt "$TMP/schema.json" --indentation 4 --check >"$TMP/output.txt" 2>&1 && CODE="$?" || CODE="$?"
 test "$CODE" = "1" || exit 1
 
-cat << EOF > "$TMP/error.txt"
-FAIL: $(realpath "$TMP")/schema.json
-Got:
-{
-  "\$schema": "http://json-schema.org/draft-04/schema#",
-  "type": 1
-}
-
-But expected:
-{
-    "\$schema": "http://json-schema.org/draft-04/schema#",
-    "type": 1
-}
+cat << EOF > "$TMP/expected.txt"
+fail: $(realpath "$TMP")/schema.json
 
+Run the \`fmt\` command without \`--check/-c\` to fix the formatting
 EOF
 
-diff "$TMP/stderr.txt" "$TMP/error.txt"
+diff "$TMP/output.txt" "$TMP/expected.txt"
 
 cat << 'EOF' > "$TMP/expected.json"
 {
diff --git a/test/format/fail_check_single_invalid.sh b/test/format/fail_check_single_invalid.sh
index 05fa77cf..eaa6bcf7 100755
--- a/test/format/fail_check_single_invalid.sh
+++ b/test/format/fail_check_single_invalid.sh
@@ -14,5 +14,14 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json" --check 2>"$TMP/output.txt" && CODE="$?" || CODE="$?"
+"$1" fmt "$TMP/schema.json" --check >"$TMP/output.txt" 2>&1 && CODE="$?" || CODE="$?"
 test "$CODE" = "1" || exit 1
+
+cat << EOF > "$TMP/expected.txt"
+error: Failed to parse the JSON document
+  at line 3
+  at column 3
+  at file path $(realpath "$TMP")/schema.json
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected.txt"
diff --git a/test/format/fail_check_single_json.sh b/test/format/fail_check_single_json.sh
new file mode 100755
index 00000000..64156e2b
--- /dev/null
+++ b/test/format/fail_check_single_json.sh
@@ -0,0 +1,32 @@
+#!/bin/sh
+
+set -o errexit
+set -o nounset
+
+TMP="$(mktemp -d)"
+clean() { rm -rf "$TMP"; }
+trap clean EXIT
+
+mkdir -p "$TMP/this/is/a/very/very/very/long/path"
+
+cat << 'EOF' > "$TMP/this/is/a/very/very/very/long/path/schema.json"
+{
+  "type": 1,
+  "$schema": "http://json-schema.org/draft-04/schema#"
+}
+EOF
+
+"$1" fmt "$TMP/this/is/a/very/very/very/long/path/schema.json" \
+  --check --json >"$TMP/output.json" 2>&1 && CODE="$?" || CODE="$?"
+test "$CODE" = "1" || exit 1
+
+cat << EOF > "$TMP/expected.json"
+{
+  "valid": false,
+  "errors": [
+    "$(realpath "$TMP")/this/is/a/very/very/very/long/path/schema.json"
+  ]
+}
+EOF
+
+diff "$TMP/output.json" "$TMP/expected.json"
diff --git a/test/format/fail_check_single_json_indentation.sh b/test/format/fail_check_single_json_indentation.sh
new file mode 100755
index 00000000..bd776ece
--- /dev/null
+++ b/test/format/fail_check_single_json_indentation.sh
@@ -0,0 +1,32 @@
+#!/bin/sh
+
+set -o errexit
+set -o nounset
+
+TMP="$(mktemp -d)"
+clean() { rm -rf "$TMP"; }
+trap clean EXIT
+
+mkdir -p "$TMP/this/is/a/very/very/very/long/path"
+
+cat << 'EOF' > "$TMP/this/is/a/very/very/very/long/path/schema.json"
+{
+  "type": 1,
+  "$schema": "http://json-schema.org/draft-04/schema#"
+}
+EOF
+
+"$1" fmt "$TMP/this/is/a/very/very/very/long/path/schema.json" \
+  --check --json --indentation 4 >"$TMP/output.json" 2>&1 && CODE="$?" || CODE="$?"
+test "$CODE" = "1" || exit 1
+
+cat << EOF > "$TMP/expected.json"
+{
+    "valid": false,
+    "errors": [
+        "$(realpath "$TMP")/this/is/a/very/very/very/long/path/schema.json"
+    ]
+}
+EOF
+
+diff "$TMP/output.json" "$TMP/expected.json"
diff --git a/test/format/fail_invalid_path.sh b/test/format/fail_invalid_path.sh
index a147ca2d..5d2dc415 100755
--- a/test/format/fail_invalid_path.sh
+++ b/test/format/fail_invalid_path.sh
@@ -7,5 +7,12 @@ TMP="$(mktemp -d)"
 clean() { rm -rf "$TMP"; }
 trap clean EXIT
 
-"$1" fmt "$TMP/does_not_exist.json" && CODE="$?" || CODE="$?"
+"$1" fmt "$TMP/does_not_exist.json" >"$TMP/output.txt" 2>&1 && CODE="$?" || CODE="$?"
 test "$CODE" = "1" || exit 1
+
+cat << EOF > "$TMP/expected.txt"
+error: No such file or directory
+  at file path $(realpath "$TMP")/does_not_exist.json
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected.txt"
diff --git a/test/format/fail_no_dialect.sh b/test/format/fail_no_dialect.sh
index c55ae527..150f2508 100755
--- a/test/format/fail_no_dialect.sh
+++ b/test/format/fail_no_dialect.sh
@@ -17,7 +17,7 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json" 2>"$TMP/stderr.txt" && CODE="$?" || CODE="$?"
+"$1" fmt "$TMP/schema.json" >"$TMP/output.txt" 2>&1 && CODE="$?" || CODE="$?"
 test "$CODE" = "1" || exit 1
 
 cat << EOF > "$TMP/expected.txt"
@@ -28,16 +28,16 @@ If the input does not declare the \`\$schema\` keyword, you might want to
 explicitly declare a default dialect using \`--default-dialect/-d\`
 EOF
 
-diff "$TMP/stderr.txt" "$TMP/expected.txt"
+diff "$TMP/output.txt" "$TMP/expected.txt"
 
 # JSON error
-"$1" fmt "$TMP/schema.json" --json >"$TMP/stdout.txt" && CODE="$?" || CODE="$?"
+"$1" fmt "$TMP/schema.json" --json >"$TMP/output_json.txt" 2>&1 && CODE="$?" || CODE="$?"
 test "$CODE" = "1" || exit 1
 
-cat << 'EOF' > "$TMP/expected.txt"
+cat << 'EOF' > "$TMP/expected_json.txt"
 {
   "error": "Could not determine the base dialect of the schema"
 }
 EOF
 
-diff "$TMP/stdout.txt" "$TMP/expected.txt"
+diff "$TMP/output_json.txt" "$TMP/expected_json.txt"
diff --git a/test/format/fail_unknown_metaschema.sh b/test/format/fail_unknown_metaschema.sh
index 6d565fdf..e1b15c7d 100755
--- a/test/format/fail_unknown_metaschema.sh
+++ b/test/format/fail_unknown_metaschema.sh
@@ -18,7 +18,7 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json" 2>"$TMP/stderr.txt" && CODE="$?" || CODE="$?"
+"$1" fmt "$TMP/schema.json" >"$TMP/output.txt" 2>&1 && CODE="$?" || CODE="$?"
 test "$CODE" = "1" || exit 1
 
 cat << EOF > "$TMP/expected.txt"
@@ -28,17 +28,17 @@ error: Could not resolve the metaschema of the schema
 This is likely because you forgot to import such schema using \`--resolve/-r\`
 EOF
 
-diff "$TMP/stderr.txt" "$TMP/expected.txt"
+diff "$TMP/output.txt" "$TMP/expected.txt"
 
 # JSON error
-"$1" fmt "$TMP/schema.json" --json >"$TMP/stdout.txt" && CODE="$?" || CODE="$?"
+"$1" fmt "$TMP/schema.json" --json >"$TMP/output_json.txt" 2>&1 && CODE="$?" || CODE="$?"
 test "$CODE" = "1" || exit 1
 
-cat << EOF > "$TMP/expected.txt"
+cat << EOF > "$TMP/expected_json.txt"
 {
   "error": "Could not resolve the metaschema of the schema",
   "identifier": "https://example.com/unknown"
 }
 EOF
 
-diff "$TMP/stdout.txt" "$TMP/expected.txt"
+diff "$TMP/output_json.txt" "$TMP/expected_json.txt"
diff --git a/test/format/pass_bignum_real.sh b/test/format/pass_bignum_real.sh
index 047ec531..3a037d24 100755
--- a/test/format/pass_bignum_real.sh
+++ b/test/format/pass_bignum_real.sh
@@ -14,7 +14,12 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json"
+"$1" fmt "$TMP/schema.json" >"$TMP/output.txt" 2>&1
+
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected.json"
 {
diff --git a/test/format/pass_check_single.sh b/test/format/pass_check_single.sh
index d0b045ba..f1242d42 100755
--- a/test/format/pass_check_single.sh
+++ b/test/format/pass_check_single.sh
@@ -14,7 +14,12 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json" --check
+"$1" fmt "$TMP/schema.json" --check >"$TMP/output.txt" 2>&1
+
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected.json"
 {
diff --git a/test/format/pass_check_single_indentation.sh b/test/format/pass_check_single_indentation.sh
index ffab28ff..8a075d07 100755
--- a/test/format/pass_check_single_indentation.sh
+++ b/test/format/pass_check_single_indentation.sh
@@ -14,7 +14,12 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json" --check --indentation 4
+"$1" fmt "$TMP/schema.json" --check --indentation 4 >"$TMP/output.txt" 2>&1
+
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected.json"
 {
diff --git a/test/format/pass_check_single_json.sh b/test/format/pass_check_single_json.sh
new file mode 100755
index 00000000..9003789d
--- /dev/null
+++ b/test/format/pass_check_single_json.sh
@@ -0,0 +1,25 @@
+#!/bin/sh
+
+set -o errexit
+set -o nounset
+
+TMP="$(mktemp -d)"
+clean() { rm -rf "$TMP"; }
+trap clean EXIT
+
+cat << 'EOF' > "$TMP/schema.json"
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "type": 1
+}
+EOF
+
+"$1" fmt "$TMP/schema.json" --check --json >"$TMP/output.json" 2>&1
+
+cat << 'EOF' > "$TMP/expected.json"
+{
+  "valid": true
+}
+EOF
+
+diff "$TMP/output.json" "$TMP/expected.json"
diff --git a/test/format/pass_check_single_keep_ordering.sh b/test/format/pass_check_single_keep_ordering.sh
index c98e7f86..8a432d16 100755
--- a/test/format/pass_check_single_keep_ordering.sh
+++ b/test/format/pass_check_single_keep_ordering.sh
@@ -14,7 +14,12 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json" --check --keep-ordering
+"$1" fmt "$TMP/schema.json" --check --keep-ordering >"$TMP/output.txt" 2>&1
+
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected.json"
 {
diff --git a/test/format/pass_check_single_verbose.sh b/test/format/pass_check_single_verbose.sh
new file mode 100755
index 00000000..78e13849
--- /dev/null
+++ b/test/format/pass_check_single_verbose.sh
@@ -0,0 +1,33 @@
+#!/bin/sh
+
+set -o errexit
+set -o nounset
+
+TMP="$(mktemp -d)"
+clean() { rm -rf "$TMP"; }
+trap clean EXIT
+
+cat << 'EOF' > "$TMP/schema.json"
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "type": 1
+}
+EOF
+
+"$1" fmt "$TMP/schema.json" --check --verbose >"$TMP/output.txt" 2>&1
+
+cat << EOF > "$TMP/expected_output.txt"
+Checking: $(realpath "$TMP")/schema.json
+ok: $(realpath "$TMP")/schema.json
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
+
+cat << 'EOF' > "$TMP/expected.json"
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "type": 1
+}
+EOF
+
+diff "$TMP/schema.json" "$TMP/expected.json"
diff --git a/test/format/pass_check_yaml.sh b/test/format/pass_check_yaml.sh
index 14bdead5..bbd6d7c7 100755
--- a/test/format/pass_check_yaml.sh
+++ b/test/format/pass_check_yaml.sh
@@ -12,12 +12,12 @@ type: 1
 $schema: http://json-schema.org/draft-04/schema#
 EOF
 
-"$1" fmt "$TMP/schema.yaml" --check 2>"$TMP/stderr.txt" && CODE="$?" || CODE="$?"
+"$1" fmt "$TMP/schema.yaml" --check >"$TMP/output.txt" 2>&1 && CODE="$?" || CODE="$?"
 test "$CODE" = "1" || exit 1
 
-cat << EOF > "$TMP/error.txt"
+cat << EOF > "$TMP/expected.txt"
 error: This command does not support YAML input files yet
   at file path $(realpath "$TMP/schema.yaml")
 EOF
 
-diff "$TMP/stderr.txt" "$TMP/error.txt"
+diff "$TMP/output.txt" "$TMP/expected.txt"
diff --git a/test/format/pass_config_path.sh b/test/format/pass_config_path.sh
index 1700363c..ebeb20d1 100755
--- a/test/format/pass_config_path.sh
+++ b/test/format/pass_config_path.sh
@@ -26,7 +26,7 @@ cat << 'EOF' > "$TMP/jsonschema.json"
 EOF
 
 cd "$TMP/bar"
-"$1" fmt --verbose 2> "$TMP/output.txt"
+"$1" fmt --verbose >"$TMP/output.txt" 2>&1
 
 cat << EOF > "$TMP/expected.txt"
 Using configuration file: $(realpath "$TMP")/jsonschema.json
diff --git a/test/format/pass_cwd.sh b/test/format/pass_cwd.sh
index 9888eafa..2347b398 100755
--- a/test/format/pass_cwd.sh
+++ b/test/format/pass_cwd.sh
@@ -21,7 +21,12 @@ cat << 'EOF' > "$TMP/schema_2.json"
 EOF
 
 cd "$TMP"
-"$1" fmt
+"$1" fmt >"$TMP/output.txt" 2>&1
+
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected_1.json"
 {
diff --git a/test/format/pass_default_dialect.sh b/test/format/pass_default_dialect.sh
index ce75267a..d2d5b869 100755
--- a/test/format/pass_default_dialect.sh
+++ b/test/format/pass_default_dialect.sh
@@ -15,7 +15,12 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json" --default-dialect "https://json-schema.org/draft/2020-12/schema"
+"$1" fmt "$TMP/schema.json" --default-dialect "https://json-schema.org/draft/2020-12/schema" >"$TMP/output.txt" 2>&1
+
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected.json"
 {
diff --git a/test/format/pass_default_dialect_config.sh b/test/format/pass_default_dialect_config.sh
index e61a2e5c..55c0f18c 100755
--- a/test/format/pass_default_dialect_config.sh
+++ b/test/format/pass_default_dialect_config.sh
@@ -21,7 +21,7 @@ cat << 'EOF' > "$TMP/jsonschema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json" --verbose 2> "$TMP/output.txt"
+"$1" fmt "$TMP/schema.json" --verbose >"$TMP/output.txt" 2>&1
 
 cat << 'EOF' > "$TMP/expected.json"
 {
@@ -36,9 +36,9 @@ EOF
 
 diff "$TMP/schema.json" "$TMP/expected.json"
 
-cat << EOF > "$TMP/expected_log.txt"
+cat << EOF > "$TMP/expected_output.txt"
 Formatting: $(realpath "$TMP")/schema.json
 Using configuration file: $(realpath "$TMP")/jsonschema.json
 EOF
 
-diff "$TMP/output.txt" "$TMP/expected_log.txt"
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
diff --git a/test/format/pass_default_dialect_config_relative.sh b/test/format/pass_default_dialect_config_relative.sh
index cf3b5a92..513018e6 100755
--- a/test/format/pass_default_dialect_config_relative.sh
+++ b/test/format/pass_default_dialect_config_relative.sh
@@ -23,7 +23,7 @@ EOF
 
 cd "$TMP"
 
-"$1" fmt schema.json --verbose 2> "$TMP/output.txt"
+"$1" fmt schema.json --verbose >"$TMP/output.txt" 2>&1
 
 cat << 'EOF' > "$TMP/expected.json"
 {
@@ -38,9 +38,9 @@ EOF
 
 diff "$TMP/schema.json" "$TMP/expected.json"
 
-cat << EOF > "$TMP/expected_log.txt"
+cat << EOF > "$TMP/expected_output.txt"
 Formatting: $(realpath "$TMP")/schema.json
 Using configuration file: $(realpath "$TMP")/jsonschema.json
 EOF
 
-diff "$TMP/output.txt" "$TMP/expected_log.txt"
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
diff --git a/test/format/pass_directory.sh b/test/format/pass_directory.sh
index 57b8ae11..aa9a43d7 100755
--- a/test/format/pass_directory.sh
+++ b/test/format/pass_directory.sh
@@ -20,7 +20,12 @@ cat << 'EOF' > "$TMP/schema_2.json"
 {"$schema": "https://json-schema.org/draft/2020-12/schema", "type": "string", "title": "My String"}
 EOF
 
-"$1" fmt "$TMP"
+"$1" fmt "$TMP" >"$TMP/output.txt" 2>&1
+
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected_1.json"
 {
diff --git a/test/format/pass_directory_ignore_directory.sh b/test/format/pass_directory_ignore_directory.sh
index ac2afd81..bbf3f85a 100755
--- a/test/format/pass_directory_ignore_directory.sh
+++ b/test/format/pass_directory_ignore_directory.sh
@@ -21,7 +21,12 @@ cat << 'EOF' > "$TMP/nested/schema_2.json"
 {"type": "string", "title": "My String"}
 EOF
 
-"$1" fmt "$TMP" --ignore "$TMP/nested"
+"$1" fmt "$TMP" --ignore "$TMP/nested" >"$TMP/output.txt" 2>&1
+
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected_1.json"
 {
diff --git a/test/format/pass_directory_ignore_file.sh b/test/format/pass_directory_ignore_file.sh
index 2216dd37..703c21ec 100755
--- a/test/format/pass_directory_ignore_file.sh
+++ b/test/format/pass_directory_ignore_file.sh
@@ -20,7 +20,12 @@ cat << 'EOF' > "$TMP/schema_2.json"
 {"type": "string", "title": "My String"}
 EOF
 
-"$1" fmt "$TMP" --ignore "$TMP/schema_2.json"
+"$1" fmt "$TMP" --ignore "$TMP/schema_2.json" >"$TMP/output.txt" 2>&1
+
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected_1.json"
 {
diff --git a/test/format/pass_multi_extension.sh b/test/format/pass_multi_extension.sh
index 6b51cbff..cfb17c5e 100755
--- a/test/format/pass_multi_extension.sh
+++ b/test/format/pass_multi_extension.sh
@@ -20,7 +20,14 @@ cat << 'EOF' > "$TMP/schema_2.schema.json"
 EOF
 
 cd "$TMP"
-"$1" fmt --extension .schema.json -v
+"$1" fmt --extension .schema.json -v >"$TMP/output.txt" 2>&1
+
+cat << EOF > "$TMP/expected_output.txt"
+Using extension: .schema.json
+Formatting: $(realpath "$TMP")/schema_2.schema.json
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected_1.json"
 {
diff --git a/test/format/pass_single.sh b/test/format/pass_single.sh
index 7c6e9c94..46f9c744 100755
--- a/test/format/pass_single.sh
+++ b/test/format/pass_single.sh
@@ -16,7 +16,12 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json"
+"$1" fmt "$TMP/schema.json" >"$TMP/output.txt" 2>&1
+
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected.json"
 {
diff --git a/test/format/pass_single_indentation.sh b/test/format/pass_single_indentation.sh
index 29f04f1e..a6278c55 100755
--- a/test/format/pass_single_indentation.sh
+++ b/test/format/pass_single_indentation.sh
@@ -16,7 +16,12 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt "$TMP/schema.json" --indentation 4
+"$1" fmt "$TMP/schema.json" --indentation 4 >"$TMP/output.txt" 2>&1
+
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected.json"
 {
diff --git a/test/format/pass_single_intact_mtime.sh b/test/format/pass_single_intact_mtime.sh
index 4e705cb7..e397c3ef 100755
--- a/test/format/pass_single_intact_mtime.sh
+++ b/test/format/pass_single_intact_mtime.sh
@@ -26,9 +26,14 @@ EOF
 mtime_old="$(mtime "$TMP/schema.json")"
 sleep 1
 
-"$1" fmt "$TMP/schema.json"
+"$1" fmt "$TMP/schema.json" >"$TMP/output.txt" 2>&1
 mtime_new="$(mtime "$TMP/schema.json")"
 
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
+
 if [ "$mtime_old" != "$mtime_new" ]
 then
   echo "The file was unexpectedly modified" 1>&2
diff --git a/test/format/pass_single_keep_ordering.sh b/test/format/pass_single_keep_ordering.sh
index c22ee47a..d563b5c0 100755
--- a/test/format/pass_single_keep_ordering.sh
+++ b/test/format/pass_single_keep_ordering.sh
@@ -15,7 +15,12 @@ cat << 'EOF' > "$TMP/schema.json"
 }
 EOF
 
-"$1" fmt --keep-ordering "$TMP/schema.json"
+"$1" fmt --keep-ordering "$TMP/schema.json" >"$TMP/output.txt" 2>&1
+
+cat << 'EOF' > "$TMP/expected_output.txt"
+EOF
+
+diff "$TMP/output.txt" "$TMP/expected_output.txt"
 
 cat << 'EOF' > "$TMP/expected.json"
 {
diff --git a/test/format/pass_yaml.sh b/test/format/pass_yaml.sh
index 5db77a8b..047da5fc 100755
--- a/test/format/pass_yaml.sh
+++ b/test/format/pass_yaml.sh
@@ -12,15 +12,15 @@ additionalProperties: false
 title: Hello World
 EOF
 
-"$1" fmt "$TMP/schema.yaml" 2>"$TMP/stderr.txt" && CODE="$?" || CODE="$?"
+"$1" fmt "$TMP/schema.yaml" >"$TMP/output.txt" 2>&1 && CODE="$?" || CODE="$?"
 test "$CODE" = "1" || exit 1
 
-cat << EOF > "$TMP/error.txt"
+cat << EOF > "$TMP/expected.txt"
 error: This command does not support YAML input files yet
   at file path $(realpath "$TMP/schema.yaml")
 EOF
 
-diff "$TMP/stderr.txt" "$TMP/error.txt"
+diff "$TMP/output.txt" "$TMP/expected.txt"
 
 cat << EOF > "$TMP/expected.yaml"
 additionalProperties: false