mktemp: fix common and standardize between variants (#10700)

* mktemp: fix `common` and standardize variants
* mktemp: add -p example
* linux/mktemp: add -p example
* linux/mktemp: mention `$TMPDIR` in the `-p` example
* osx/mktemp: add page
* linux/mktemp: fix errors
* linux/mktemp: add serial comma

pages/common/mktemp.md

@@ -1,16 +1,24 @@
 # mktemp
 
 > Create a temporary file or directory.
-> More information: <https://ss64.com/osx/mktemp.html>.
+> More information: <https://man.openbsd.org/mktemp.1>.
 
-- Create an empty temporary file and print the absolute path to it:
+- Create an empty temporary file and print its absolute path:
 
 `mktemp`
 
-- Create an empty temporary file with a given suffix and print the absolute path to file:
+- Use a custom directory if `$TMPDIR` is not set (the default is platform-dependent, but usually `/tmp`):
 
-`mktemp --suffix "{{.ext}}"`
+`mktemp -p {{/path/to/tempdir}}`
 
-- Create a temporary directory and print the absolute path to it:
+- Use a custom path template (`X`s are replaced with random alphanumeric characters):
+
+`mktemp {{/tmp/example.XXXXXXXX}}`
+
+- Use a custom file name template:
+
+`mktemp -t {{example.XXXXXXXX}}`
+
+- Create an empty temporary directory and print its absolute path:
 
 `mktemp -d`