Added: Cal, srm, md5, md5sum, xed

Edited cp and rm. Fixed markdown escaping the wildcard.

linux/md5sum.md

@@ -0,0 +1,13 @@
+# md5sum
+
+> Calculate MD5 cryptographic checksums
+
+- Calculate the MD5 checksum for file(s) or files in a directory, one checksum per file
+
+`md5sum {{filename1}}`
+`md5sum {{filename1}} {{filename2}}`
+`md5sum {{directory/\*}}`
+
+- Read a file of MD5SUMs and verify all files have matching checksums
+
+`md5sum -c {{filename.md5}}`