md5sum Command

Purpose

Computes or verifies 128-bit message digests algorithm 5 (MD5) checksum of files.

Syntax

md5sum [ -b ] [ -c ] [ -h ] [ -t ] [ --tag ] [ -V ] [ checksum_file ] [ file ]...

Description

The md5sum command computes or verifies 128-bit MD5 checksum of files. In PowerVC virtual appliance, only read-only checksum computation and verification are allowed for security. File creation, modification, or advanced options are not allowed.

Flags

Table 1. Flags
Items	Description
-b	Reads file in binary mode. This behavior is the default behavior in Unix. The -b flag treats input as raw bytes and ignores newline conversions.
-c	Reads MD5 checksum from a file and verifies it against actual files. Reports OK or FAILED. The -c flag returns OK if the match is successful, otherwise it returns FAILED.
-h or --help	Displays help about the md5sum command.
-t	Reads file in text mode. The -t flag converts the Carriage Return Line Feed (CRLF) line endings in the input to Line Feed (LF). This flag must be used for cross-platform consistency.
--tag	Generates a Berkeley Software Distribution (BSD) style output. The output is displayed in the following format: `MD5 (filename) = checksum` This option is useful for compatibility with bsdsum or older tools.
-V or --version	Displays version information.

Positional arguments

Table 2. Positional arguments
Item	Description
`file`	Specifies the file name that must be read. Multiple file names can be specifies separated by a white space. This option is mandatory with all the flags except the -c flag.
`checksum_file`	Specifies a file that contains pre-computed checksum lines to verify against the actual files. This option is mandatory with the -c flag.

Examples

To compute MD5 of a single file (default binary mode), enter the following command:
```
md5sum document.pdf
```
To compute checksum of multiple files, enter the following command:
```
md5sum *.jpg
```
To compute from the standard input (stdin), enter the following command:
```
echo -n "hello" | md5sum
```
To read files in text mode, enter the following command:
```
md5sum -t report.txt
```
To display BSD-style output, enter the following command:
```
md5sum --tag config.ini
```
To create a checksum file, enter the following command:
```
md5sum *.bin > backups.md5
```
To verify files against a checksum file, enter the following command:
```
md5sum -c backups.md5
```
To check a single file by using a checksum file, enter the following command:
```
md5sum -c checksums.txt
```