# sha1sum > Calculate SHA1 cryptographic checksums. > More information: . - Calculate the SHA1 checksum for a file: `sha1sum {{path/to/file}}` - Calculate SHA1 checksums for multiple files: `sha1sum {{path/to/file1}} {{path/to/file2}}` - Calculate and save the list of SHA1 checksums to a file: `sha1sum {{path/to/file1}} {{path/to/file2}} > {{path/to/file.sha1}}` - Read a file of SHA1 sums and verify all files have matching checksums: `sha1sum --check {{path/to/file.sha1}}` - Only show a message for missing files or when verification fails: `sha1sum --check --quiet {{path/to/file.sha1}}` - Only show a message for files for which verification fails, ignoring missing files: `sha1sum --ignore-missing --check --quiet {{path/to/file.sha1}}`