sxiv: add page (#4806)

pages/linux/sxiv.md

@@ -0,0 +1,24 @@
+# sxiv
+
+> Simple X Image Viewer.
+> More information: <https://github.com/muennich/sxiv>.
+
+- Open an image:
+
+`sxiv {{path/to/file}}`
+
+- Open an image in fullscreen mode:
+
+`sxiv -f {{path/to/file}}`
+
+- Open a newline-separated list of images, reading filenames from standard input:
+
+`echo {{path/to/file}} | sxiv -i`
+
+- Open a space-separated list of images as a slideshow:
+
+`sxiv -S {{seconds}} {{path/to/file}}`
+
+- Open a space-separated list of images in thumbnail mode:
+
+`sxiv -t {{path/to/file}}`