unar: add page (#1141)

pages/common/unar.md

@@ -0,0 +1,23 @@
+# unar
+
+> Extract contents from archive files.
+
+- Extract an archive to the current directory:
+
+`unar {{archive}}`
+
+- Extract an archive to the specified directory:
+
+`unar -o {{path/to/directory}} {{archive}}`
+
+- Force overwrite if files to be unpacked already exist:
+
+`unar -f {{archive}}`
+
+- Force rename if files to be unpacked already exist:
+
+`unar -r {{archive}}`
+
+- Force skip if files to be unpacked already exist:
+
+`unar -s {{archive}}`