diff --git a/cmd/holotreeHash.go b/cmd/holotreeHash.go
index d545161..a1e2660 100644
--- a/cmd/holotreeHash.go
+++ b/cmd/holotreeHash.go
@@ -2,8 +2,12 @@ package cmd
 
 import (
 	"fmt"
+	"io"
+	"os"
+	"strings"
 
 	"github.com/robocorp/rcc/common"
+	"github.com/robocorp/rcc/conda"
 	"github.com/robocorp/rcc/htfs"
 	"github.com/robocorp/rcc/operations"
 	"github.com/robocorp/rcc/pretty"
@@ -12,7 +16,8 @@ import (
 )
 
 var (
-	holotreeShowBlueprint bool
+	holotreeShowBlueprint      bool
+	holotreeReadInputFromStdin bool
 )
 
 var holotreeHashCmd = &cobra.Command{
@@ -24,8 +29,31 @@ var holotreeHashCmd = &cobra.Command{
 		if common.DebugFlag() {
 			defer common.Stopwatch("Conda YAML hash calculation lasted").Report()
 		}
-		_, holotreeBlueprint, err := htfs.ComposeFinalBlueprint(args, "", common.DevDependencies)
-		pretty.Guard(err == nil, 1, "Blueprint calculation failed: %v", err)
+
+		var err error
+		if holotreeReadInputFromStdin {
+			// Now, read from stdin until EOF and use that as the input to calculate the blueprint hash.
+			data, err := io.ReadAll(os.Stdin)
+			pretty.Guard(err == nil, 1, "Failed to read from stdin: %v", err)
+
+			if len(args) != 1 {
+				common.Fatal("When reading from stdin, the target file path must be provided as the first (and only) argument.", nil)
+			}
+
+			filename := args[0]
+			if !strings.HasSuffix(filename, ".yaml") {
+				common.Fatal("When reading from stdin, the target file path must be provided as the first (and only) argument and it must be a `.yaml` file.", nil)
+			}
+
+			environment, err := conda.ReadPackageCondaYamlFromContents(data, filename, common.DevDependencies)
+			pretty.Guard(err == nil, 1, "Failed to read from stdin: %v (filename: %q)", err, filename)
+
+			holotreeBlueprint, err = htfs.BlueprintFromEnvironment(environment)
+			pretty.Guard(err == nil, 1, "Failed to calculate blueprint from environment: %v", err)
+		} else {
+			_, holotreeBlueprint, err = htfs.ComposeFinalBlueprint(args, "", common.DevDependencies)
+			pretty.Guard(err == nil, 1, "Blueprint calculation failed: %v", err)
+		}
 		hash := common.BlueprintHash(holotreeBlueprint)
 
 		common.Log("Blueprint hash for %v is %v.", args, hash)
@@ -59,4 +87,5 @@ func init() {
 	holotreeHashCmd.Flags().BoolVarP(&common.DevDependencies, "devdeps", "", false, "Include dev-dependencies from the `package.yaml` when calculating the hash (only valid when dealing with a `package.yaml` file).")
 	holotreeHashCmd.Flags().BoolVarP(&holotreeJson, "json", "j", false, "Show environment as JSON.")
 	holotreeHashCmd.Flags().BoolVarP(&holotreeShowBlueprint, "show-blueprint", "", false, "Show full blueprint, not just hash.")
+	holotreeHashCmd.Flags().BoolVarP(&holotreeReadInputFromStdin, "stdin", "", false, "Read the conda.yaml/package.yaml contents from stdin.")
 }
diff --git a/common/version.go b/common/version.go
index f29db10..97c7cca 100644
--- a/common/version.go
+++ b/common/version.go
@@ -1,5 +1,5 @@
 package common
 
 const (
-	Version = `v18.4.0`
+	Version = `v18.5.0`
 )
diff --git a/conda/condayaml.go b/conda/condayaml.go
index 04b2316..d0a1241 100644
--- a/conda/condayaml.go
+++ b/conda/condayaml.go
@@ -2,11 +2,9 @@ package conda
 
 import (
 	"fmt"
-	"os"
 	"regexp"
 	"strings"
 
-	"github.com/robocorp/rcc/cloud"
 	"github.com/robocorp/rcc/common"
 	"github.com/robocorp/rcc/pathlib"
 
@@ -658,21 +656,6 @@ func CondaYamlFrom(content []byte) (*Environment, error) {
 	return result.AsEnvironment(), nil
 }
 
-func readCondaYaml(filename string) (*Environment, error) {
-	var content []byte
-	var err error
-
-	if pathlib.IsFile(filename) {
-		content, err = os.ReadFile(filename)
-	} else {
-		content, err = cloud.ReadFile(filename)
-	}
-	if err != nil {
-		return nil, fmt.Errorf("%q: %w", filename, err)
-	}
-	return CondaYamlFrom(content)
-}
-
 func pipContent(result []*Dependency, value interface{}) []*Dependency {
 	values, ok := value.([]interface{})
 	if !ok {
diff --git a/conda/packageyaml.go b/conda/packageyaml.go
index 64ed746..615b0bd 100644
--- a/conda/packageyaml.go
+++ b/conda/packageyaml.go
@@ -7,7 +7,6 @@ import (
 	"strings"
 
 	"github.com/robocorp/rcc/cloud"
-	"github.com/robocorp/rcc/common"
 	"github.com/robocorp/rcc/pathlib"
 	"gopkg.in/yaml.v2"
 )
@@ -90,25 +89,19 @@ func packageYamlFrom(content []byte, devDependencies bool) (*Environment, error)
 	return result.AsEnvironment(devDependencies), nil
 }
 
-func ReadPackageCondaYaml(filename string, devDependencies bool) (*Environment, error) {
+func ReadPackageCondaYamlFromContents(content []byte, filename string, devDependencies bool) (*Environment, error) {
 	basename := strings.ToLower(filepath.Base(filename))
 	if basename == "package.yaml" {
-		environment, err := readPackageYaml(filename, devDependencies)
-		if err == nil {
-			return environment, nil
-		}
+		return packageYamlFrom(content, devDependencies)
 	}
 	if devDependencies {
 		// error: only valid when dealing with a `package.yaml` file
 		return nil, fmt.Errorf("'--devdeps' flag is only valid when dealing with a `package.yaml` file. Current file: %q", filename)
 	}
-	return readCondaYaml(filename)
+	return CondaYamlFrom(content)
 }
 
-func readPackageYaml(filename string, devDependencies bool) (*Environment, error) {
-	if devDependencies {
-		common.Debug("Reading file %q with dev dependencies", filename)
-	}
+func ReadPackageCondaYaml(filename string, devDependencies bool) (*Environment, error) {
 	var content []byte
 	var err error
 
@@ -120,5 +113,6 @@ func readPackageYaml(filename string, devDependencies bool) (*Environment, error
 	if err != nil {
 		return nil, fmt.Errorf("%q: %w", filename, err)
 	}
-	return packageYamlFrom(content, devDependencies)
+
+	return ReadPackageCondaYamlFromContents(content, filename, devDependencies)
 }
diff --git a/docs/changelog.md b/docs/changelog.md
index 4edcd06..c26c9fa 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -1,5 +1,11 @@
 # rcc change log
 
+## v18.5.0 (date: 25.10.2024)
+
+- support `--stdin` flag in `rcc holotree hash` to read the package file content from stdin
+  (note that the actual package file path still is expected to be given as an
+  argument, but its contents will be read from stdin instead).
+
 ## v18.4.0 (date: 25.10.2024)
 
 - support `--show-blueprint` flag in `rcc holotree hash` to show blueprint.
diff --git a/htfs/commands.go b/htfs/commands.go
index 4d3093b..fbcd0bc 100644
--- a/htfs/commands.go
+++ b/htfs/commands.go
@@ -270,12 +270,17 @@ func ComposeFinalBlueprint(userFiles []string, packfile string, devDependencies
 		fail.On(err != nil, "Failure: %v", err)
 	}
 	fail.On(right == nil, "Missing environment specification(s).")
-	content, err := right.AsYaml()
-	fail.On(err != nil, "YAML error: %v", err)
-	blueprint = []byte(strings.TrimSpace(content))
+	blueprint, err = BlueprintFromEnvironment(right)
+	fail.On(err != nil, "Blueprint from environment error: %v", err)
 	if !right.IsCacheable() {
 		fingerprint := common.BlueprintHash(blueprint)
 		pretty.Warning("Holotree blueprint %q is not publicly cacheable. Use `rcc robot diagnostics` to find out more.", fingerprint)
 	}
 	return config, blueprint, nil
 }
+
+func BlueprintFromEnvironment(environment *conda.Environment) ([]byte, error) {
+	content, err := environment.AsYaml()
+	fail.On(err != nil, "YAML error: %v", err)
+	return []byte(strings.TrimSpace(content)), nil
+}
diff --git a/robot_tests/__init__.robot b/robot_tests/__init__.robot
index 8cd35f3..1146ec9 100644
--- a/robot_tests/__init__.robot
+++ b/robot_tests/__init__.robot
@@ -1,5 +1,5 @@
 *** Settings ***
 Resource    resources.robot
-Suite Setup     Prepare Local
-Suite Teardown  Clean Local
 
+Suite Setup         Prepare Local
+Suite Teardown      Clean Local
diff --git a/robot_tests/expected/ht_hash/ht_hash_txt_conda.txt b/robot_tests/expected/ht_hash/ht_hash_txt_conda.txt
new file mode 100644
index 0000000..3c332bc
--- /dev/null
+++ b/robot_tests/expected/ht_hash/ht_hash_txt_conda.txt
@@ -0,0 +1 @@
+Blueprint hash for [robot_tests/conda.yaml] is 79ba58276b645f09.
\ No newline at end of file
diff --git a/robot_tests/ht_hash.robot b/robot_tests/ht_hash.robot
index 91711ad..034a4f6 100644
--- a/robot_tests/ht_hash.robot
+++ b/robot_tests/ht_hash.robot
@@ -49,3 +49,45 @@ Goal: Check that hash command works correctly with devdeps
     ...
     ...    robot_tests/expected/ht_hash/ht_hash_devdeps_txt.txt
     ...    use_stream=stderr
+
+Goal: Check that hash command works reading from stdin
+    Run And Check Expected Output
+    ...    build/rcc holotree hash --json --show-blueprint --devdeps --controller citests --stdin package.yaml
+    ...
+    ...    robot_tests/expected/ht_hash/ht_hash_devdeps_json_show.txt
+    ...    pass_file_as_stdin=robot_tests/bare_action/package.yaml
+
+    Run And Check Expected Output
+    ...    build/rcc holotree hash --json --devdeps --controller citests --stdin package.yaml
+    ...
+    ...    robot_tests/expected/ht_hash/ht_hash_devdeps_json.txt
+    ...    pass_file_as_stdin=robot_tests/bare_action/package.yaml
+
+    Run And Check Expected Output
+    ...    build/rcc holotree hash --show-blueprint --devdeps --controller citests --stdin robot_tests/bare_action/package.yaml
+    ...
+    ...    robot_tests/expected/ht_hash/ht_hash_devdeps_txt_show.txt
+    ...    use_stream=stderr
+    ...    pass_file_as_stdin=robot_tests/bare_action/package.yaml
+
+    Run And Check Expected Output
+    ...    build/rcc holotree hash --devdeps --controller citests --stdin robot_tests/bare_action/package.yaml
+    ...
+    ...    robot_tests/expected/ht_hash/ht_hash_devdeps_txt.txt
+    ...    use_stream=stderr
+    ...    pass_file_as_stdin=robot_tests/bare_action/package.yaml
+
+    # Check conda with stdin in the same
+    Run And Check Expected Output
+    ...    build/rcc holotree hash --controller citests --stdin robot_tests/conda.yaml
+    ...
+    ...    robot_tests/expected/ht_hash/ht_hash_txt_conda.txt
+    ...    use_stream=stderr
+    ...    pass_file_as_stdin=robot_tests/conda.yaml
+
+    # Check conda without stdin in the same
+    Run And Check Expected Output
+    ...    build/rcc holotree hash --controller citests robot_tests/conda.yaml
+    ...
+    ...    robot_tests/expected/ht_hash/ht_hash_txt_conda.txt
+    ...    use_stream=stderr
diff --git a/robot_tests/supporting.py b/robot_tests/supporting.py
index 5169617..fa1e54b 100644
--- a/robot_tests/supporting.py
+++ b/robot_tests/supporting.py
@@ -2,6 +2,7 @@
 import logging
 import subprocess
 import sys
+from pathlib import Path
 
 log = logging.getLogger(__name__)
 
@@ -61,6 +62,7 @@ def run_and_return_code_output_error(
     env: dict[str, str] | None = None,
     cwd: str | None = None,
     check: bool = False,
+    stdin_contents: str | None = None,
 ) -> tuple[int, str, str]:
     command = fix_command(command)
     cwd = get_cwd() if cwd is None else cwd
@@ -71,10 +73,13 @@ def run_and_return_code_output_error(
         shell=True,
         stderr=subprocess.PIPE,
         stdout=subprocess.PIPE,
+        stdin=subprocess.PIPE if stdin_contents else None,
         cwd=cwd,
         env=env,
     )
-    out, err = task.communicate()
+    out, err = task.communicate(
+        input=stdin_contents.encode("utf-8") if stdin_contents else None
+    )
     if check:
         assert (
             task.returncode == 0
@@ -114,11 +119,17 @@ def normalize_output(output: str) -> str:
 
 
 def run_and_check_expected_output(
-    command: str, expected_output: str, expected_file: str, use_stream: str = "stdout"
+    command: str,
+    expected_output: str,
+    expected_file: str,
+    use_stream: str = "stdout",
+    pass_file_as_stdin: Path | None = None,
 ):
-    from pathlib import Path
+    stdin_contents = pass_file_as_stdin.read_text() if pass_file_as_stdin else None
 
-    ret, out, err = run_and_return_code_output_error(command)
+    ret, out, err = run_and_return_code_output_error(
+        command, stdin_contents=stdin_contents
+    )
     assert (
         ret == 0
     ), f"Unexpected exit code {ret!r} from {command!r} with output: {out!r} and error: {err!r}"