[DOCs] Added examples and warnings about spaces in names

- For the replace pre-flights

Related to #366

README.md

@@ -445,9 +445,9 @@ This section is used to specify tasks that will be executed before generating an
         This preflight modifies the PCB. Even when a back-up is done use it carefully.
   * Valid keys:
     - `date_command`: [string=''] Command to get the date to use in the PCB.\
-                      ```git log -1 --format='%as' -- $KIBOT_PCB_NAME```\
+                      ```git log -1 --format='%as' -- "$KIBOT_PCB_NAME"```\
                       Will return the date in YYYY-MM-DD format.\
-                      ```date -d @`git log -1 --format='%at' -- $KIBOT_PCB_NAME` +%Y-%m-%d_%H-%M-%S```\
+                      ```date -d @`git log -1 --format='%at' -- "$KIBOT_PCB_NAME"` +%Y-%m-%d_%H-%M-%S```\
                       Will return the date in YYYY-MM-DD_HH-MM-SS format.\
                       Important: on KiCad 6 the title block data is optional.
                       This command will work only if you have a date in the PCB/Schematic.
@@ -472,9 +472,9 @@ This section is used to specify tasks that will be executed before generating an
         This preflight modifies the schematics. Even when a back-up is done use it carefully.
   * Valid keys:
     - `date_command`: [string=''] Command to get the date to use in the SCH.\
-                      ```git log -1 --format='%as' -- $KIBOT_SCH_NAME```\
+                      ```git log -1 --format='%as' -- "$KIBOT_SCH_NAME"```\
                       Will return the date in YYYY-MM-DD format.\
-                      ```date -d @`git log -1 --format='%at' -- $KIBOT_SCH_NAME` +%Y-%m-%d_%H-%M-%S```\
+                      ```date -d @`git log -1 --format='%at' -- "$KIBOT_SCH_NAME"` +%Y-%m-%d_%H-%M-%S```\
                       Will return the date in YYYY-MM-DD_HH-MM-SS format.\
                       Important: on KiCad 6 the title block data is optional.
                       This command will work only if you have a date in the SCH/Schematic.
@@ -497,6 +497,10 @@ This section is used to specify tasks that will be executed before generating an
     - `after`: [string=''] Text to add after the output of `command`.
     - `before`: [string=''] Text to add before the output of `command`.
     - `command`: [string=''] Command to execute to get the text, will be used only if `text` is empty.
+                 This command will be executed using the Bash shell.
+                 Be careful about spaces in file names (i.e. use "$KIBOT_PCB_NAME").
+                 The `KIBOT_PCB_NAME` environment variable is the PCB file and the
+                 `KIBOT_SCH_NAME` environment variable is the schematic file.
     - `expand_kibot_patterns`: [boolean=true] Expand %X patterns. The context is `schematic`.
     - `name`: [string=''] Name of the variable. The `version` variable will be expanded using `${version}`.
     - `text`: [string=''] Text to insert instead of the variable.

docs/samples/generic_plot.kibot.yaml

@@ -75,7 +75,7 @@ preflight:
   # The KiCad project file is modified.
   set_text_variables:
     - name: 'git_hash'
-      command: 'git log -1 --format="%h" $KIBOT_PCB_NAME'
+      command: 'git log -1 --format="%h" "$KIBOT_PCB_NAME"'
       before: 'Git hash: <'
       after: '>'
   # [boolean=false] Update the QR codes.

kibot/pre_any_replace.py

@@ -54,9 +54,9 @@ class Base_ReplaceOptions(Optionable):
         with document:
             self.date_command = ''
             """ Command to get the date to use in the PCB.\\
-                ```git log -1 --format='%as' -- $KIBOT_PCB_NAME```\\
+                ```git log -1 --format='%as' -- \"$KIBOT_PCB_NAME\"```\\
                 Will return the date in YYYY-MM-DD format.\\
-                ```date -d @`git log -1 --format='%at' -- $KIBOT_PCB_NAME` +%Y-%m-%d_%H-%M-%S```\\
+                ```date -d @`git log -1 --format='%at' -- \"$KIBOT_PCB_NAME\"` +%Y-%m-%d_%H-%M-%S```\\
                 Will return the date in YYYY-MM-DD_HH-MM-SS format.\\
                 Important: on KiCad 6 the title block data is optional.
                 This command will work only if you have a date in the PCB/Schematic """

kibot/pre_set_text_variables.py

@@ -41,7 +41,11 @@ class KiCadVariable(Optionable):
             self.text = ''
             """ Text to insert instead of the variable """
             self.command = ''
-            """ Command to execute to get the text, will be used only if `text` is empty """
+            """ Command to execute to get the text, will be used only if `text` is empty.
+                This command will be executed using the Bash shell.
+                Be careful about spaces in file names (i.e. use "$KIBOT_PCB_NAME").
+                The `KIBOT_PCB_NAME` environment variable is the PCB file and the
+                `KIBOT_SCH_NAME` environment variable is the schematic file """
             self.before = ''
             """ Text to add before the output of `command` """
             self.after = ''
@@ -91,7 +95,7 @@ class Set_Text_Variables(BasePreFlight):  # noqa: F821
     def get_example(cls):
         """ Returns a YAML value for the example config """
         return ("\n    - name: 'git_hash'"
-                "\n      command: 'git log -1 --format=\"%h\" $KIBOT_PCB_NAME'"
+                "\n      command: 'git log -1 --format=\"%h\" \"$KIBOT_PCB_NAME\"'"
                 "\n      before: 'Git hash: <'"
                 "\n      after: '>'")
 
@@ -132,7 +136,10 @@ class Set_Text_Variables(BasePreFlight):  # noqa: F821
                 result = run(cmd, stdout=PIPE, stderr=PIPE, universal_newlines=True)
                 if result.returncode:
                     logger.error('Failed to execute:\n{}\nreturn code {}'.format(r.command, result.returncode))
-                    logger.error('stdout:\n{}\nstderr:\n{}'.format(result.stdout, result.stderr))
+                    if result.stdout:
+                        logger.error('stdout:\n{}'.format(result.stdout))
+                    if result.stderr:
+                        logger.error('stderr:\n{}'.format(result.stderr))
                     sys.exit(FAILED_EXECUTE)
                 if not result.stdout:
                     logger.warning(W_EMPTREP+"Empty value from `{}`".format(r.command))