Add update_usage.py script

CONTRIBUTING.md

@@ -8,3 +8,5 @@ Please follow the next recommendations for your pull requests:
 - use `cargo fmt`
 - check the output of `cargo clippy --all-features --all --tests`
 - run tests `cargo test`
+- if you have updated usage of any casr tool, you could simply run
+  `update_usage.py` to change the `docs/usage.md` file properly

README.md

@@ -220,6 +220,8 @@ Please follow the next recommendations for your pull requests:
 - use `cargo fmt`
 - check the output of `cargo clippy --all-features --all --tests`
 - run tests `cargo test`
+- if you have updated usage of any casr tool, you could simply run
+  `update_usage.py` to change the `docs/usage.md` file properly
 
 ## Cite Us
 

update_usage.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+
+import re, sys, os
+import subprocess
+from subprocess import Popen, PIPE
+
+if __name__ == "__main__":
+    with open('docs/usage.md') as f:
+      content = f.read()
+
+    command = subprocess.run(["cargo", "build"])
+    if command.returncode != 0:
+        print('Cargo build exited with code ' + str(command.returncode))
+        exit(command.returncode)
+
+    build_dir = os.path.dirname(os.path.realpath(__file__))
+    target_dir = os.path.join(build_dir, "target", "debug")
+
+    for p in os.listdir(target_dir):
+        if p.startswith("casr-") \
+                and os.path.isfile(target := os.path.join(target_dir, p)) \
+                and os.access(target, os.X_OK):
+            command = Popen([target, "-h"], stdout=PIPE, stderr=PIPE)
+            out, _ = command.communicate()
+            output = str(out, 'utf-8', errors='ignore')
+            splitted = output.split('\n\n')
+            number_of_sections = len(splitted)
+            if number_of_sections != 4 and number_of_sections != 3:
+                print('Bad format in help message: ' + p)
+                continue
+            for i in range(1, number_of_sections):
+                splitted[i] = '\n'.join(['    ' + line for line in splitted[i].split('\n') if line])
+            new_message = '\n\n'.join(splitted) + '\n\n'
+            content = re.sub(f'## {p}\n\n' + '(.|\n)*?\n\n(\s+.*\n\n?)+', \
+                             f'## {p}\n\n' + new_message, \
+                             content)
+
+    with open('docs/usage.md', 'w') as f:
+      f.write(content)