sha512sum: fix file names

pages/common/sha512sum.md

@@ -5,20 +5,20 @@
 
 - Calculate the SHA512 checksum for a file:
 
-`sha512sum {{filename1}}`
+`sha512sum {{path/to/file}}`
 
 - Calculate SHA512 checksums for multiple files:
 
-`sha512sum {{filename1}} {{filename2}}`
+`sha512sum {{path/to/file1}} {{path/to/file2}}`
 
 - Calculate and save the list of SHA512 checksums to a file:
 
-`sha512sum {{filename1}} {{filename2}} > {{filename.sha512}}`
+`sha512sum {{path/to/file1}} {{path/to/file2}} > {{path/to/file.sha512}}`
 
 - Read a file of SHA512 sums and verify all files have matching checksums:
 
-`sha512sum --check {{filename.sha512}}`
+`sha512sum --check {{path/to/file.sha512}}`
 
 - Only show a message for files for which verification fails:
 
-`sha512sum --check --quiet {{filename.sha512}}`
+`sha512sum --check --quiet {{path/to/file.sha512}}`