Add best practices section

docs/en/src/writing-plugins.md

@@ -19,8 +19,7 @@ A minimal plugin should confirm to the following structure:
 └── init.lua
 ```
 
-You can also use
-[this template][2].
+You can also use [this template][2].
 
 ### README.md
 
@@ -51,6 +50,18 @@ to append `.xplr` to the name to make them distinguishable. Similar to the
 Finally, after publishing, don't hesitate to
 [let us know][4].
 
+## Best practices
+
+- Try not to execute a lot of commands at startup, it may make xplr slow to
+  start.
+- When executing commands, prefer `Call0` over `Call`, `BashExec0` over
+  `BashExec` and so on. File names may contain newline characters
+  (e.g. `foo$'\n'bar`).
+- File names may also contain quotes. Use the syntax
+  `printf 'Call0: "%s"' "${FOO_ESC}"` where `FOO_ESC=${FOO//\"/\\\"}`.
+- Check for empty variables using the syntax `${FOO:?}` or use a default value
+  `${FOO:-defaultvalue}`.
+
 ## Examples
 
 Visit [Awesome Plugins][5] for xplr plugin examples.

src/init.lua

@@ -1803,9 +1803,9 @@ xplr.config.modes.builtin.delete = {
                   fi
                 else
                   if rm -v -- "${LINE:?}"; then
-                    printf 'LogSuccess: "%s"\0' "$line deleted" >> "${XPLR_PIPE_MSG_IN:?}"
+                    printf 'LogSuccess: "%s"\0' "$LINE_ESC deleted" >> "${XPLR_PIPE_MSG_IN:?}"
                   else
-                    printf 'LogError: "%s"\0' "Failed to delete $line" >> "${XPLR_PIPE_MSG_IN:?}"
+                    printf 'LogError: "%s"\0' "Failed to delete $LINE_ESC" >> "${XPLR_PIPE_MSG_IN:?}"
                   fi
                 fi
               done < "${XPLR_PIPE_RESULT_OUT:?}")