fselect: add page (#2975)

pages/common/fselect.md

@@ -0,0 +1,24 @@
+# fselect
+
+> Find files with SQL-like queries.
+> More information: <https://github.com/jhspetersson/fselect>.
+
+- Select full path and size from temporary or config files in a given directory:
+
+`fselect size, path from {{path/to/directory}} where name = {{'*.cfg'}} or name = {{'*.tmp'}}`
+
+- Find square images:
+
+`fselect path from {{path/to/directory}} where width = height`
+
+- Find old-school rap 320kbps MP3 files:
+
+`fselect path from {{path/to/directory}} where genre = {{Rap}} and bitrate = {{320}} and mp3_year lt {{2000}}`
+
+- Select only the first 5 results and output as JSON:
+
+`fselect size, path from {{path/to/directory}} limit {{5}} into json`
+
+- Use SQL aggregate functions to calculate minimum, maximum and average size of files in a directory:
+
+`fselect "{{MIN(size), MAX(size), AVG(size), SUM(size), COUNT(*)}} from {{path/to/directory}}"`