shasum: add page

pages/common/shasum.md

@@ -0,0 +1,23 @@
+# shasum
+
+> Calculate or check cryptographic SHA checksums.
+
+- Calculate the SHA1 checksum for a file:
+
+`shasum {{filename}}`
+
+- Calculate the SHA256 checksum for a file:
+
+`shasum -a 256 {{filename}}`
+
+- Calculate the SHA512 checksum for multiple files:
+
+`shasum -a 512 {{filename1}} {{filename2}}`
+
+- Check a file with a list of sums against the directorys files:
+
+`shasum -c {{list_file}}`
+
+- Calculate the SHA1 checksum from stdin:
+
+`{{somecommand}} | shasum`