whereis: add page (#1708)

pages/linux/whereis.md

@@ -0,0 +1,19 @@
+# whereis
+
+> Locate the binary, source, and manual page files for a command.
+
+- Locate binary, source and man pages for ssh:
+
+`whereis {{ssh}}`
+
+- Locate binary and man pages for ls:
+
+`whereis -bm {{ls}}`
+
+- Locate source of gcc and man pages for git:
+
+`whereis -s {{gcc}} -m {{git}}`
+
+- Locate binaries for gcc in /usr/bin/ only:
+
+`whereis -b -B {{/usr/bin/}} -f {{gcc}}`