filecheck

Match input_file content with pattern file check_file

$ FileCheck --input-file=[path/to/input_file] [path/to/check_file]

$ echo "[some_text]" | FileCheck [path/to/check_file]

$ echo "[some_text]" | FileCheck --check-prefix=[prefix] [path/to/check_file]

$ echo "[some_text]" | FileCheck -v [path/to/check_file]

$ llvm-as [path/to/llvm_code.ll] | FileCheck [path/to/check_file]

`filecheck` [options] [file...]

-h, --help
    Display help information and exit.

-v, --verbose
    Enable verbose output, showing more details about the checks performed.

-c, --checksum
    Specify the checksum algorithm to use (e.g., md5, sha256, sha512). If not specified, a default algorithm may be used.

-f, --checksum-file
    Specify a file containing checksums to compare against. Each line should typically be in the format ` `.

-q, --quiet
    Suppress all output except for errors.

[file...]
    The list of files to check. If no files are specified, the command might check all files in the current directory or read from standard input.

The `filecheck` command, while not a standard, universally available Linux utility, typically refers to a custom script or program designed to verify the integrity and validity of files. The exact functionality depends heavily on its implementation. A general-purpose `filecheck` utility might calculate checksums (like MD5, SHA-256, or SHA-512) of files and compare them against previously stored checksums to detect modifications or corruption. It could also perform other validation checks, such as verifying file signatures, file sizes, file types, or specific content patterns.

The purpose of a `filecheck` command is usually to ensure that files haven't been tampered with, either maliciously or accidentally, and that they meet expected criteria. This is particularly important in security-sensitive contexts, software distribution, or data archiving, where data integrity is critical. Because the command isn't standard, users need to create their own or rely on pre-existing ones, implementing their desired file integrity checks, so one filecheck version can be quite different from another one.

Because 'filecheck' is not a standard Linux command, its behavior and available options can vary widely depending on the specific implementation. Always refer to the documentation or help output (`filecheck -h`) for the version you are using. The example options provided here are indicative of common features in file integrity verification tools.

The exit status of `filecheck` usually indicates the success or failure of the checks. A zero exit status typically means all files passed the checks, while a non-zero status indicates errors or failed checks.

When creating a custom `filecheck` script, consider these key aspects:
1. Checksum Algorithms: Select secure and appropriate algorithms (e.g., SHA-256 or SHA-512). MD5 is considered cryptographically broken and should be avoided for security-sensitive applications.
2. Error Handling: Implement robust error handling to gracefully deal with missing files, incorrect checksums, and other potential issues.
3. Configuration: Allow for customization through command-line options or configuration files.

md5sum(1), sha256sum(1), sha512sum(1), gpg(1)