vigr

Edit the group file

$ vigr

$ vigr [[-V|--version]]

vigr [OPTIONS]

--help
    Displays a help message and exits.

--version
    Displays version information and exits.

--root CHROOT_DIR
    Applies changes within the specified CHROOT_DIR directory, allowing operation on group files in a chroot environment.

The vigr command provides a secure and robust method for editing the system's group database files, specifically /etc/group and /etc/gshadow.

It operates by first locking these critical files to prevent simultaneous modifications and data corruption. Subsequently, it creates temporary copies of the files, which are then opened in the user's preferred text editor (defaulting to vi or the editor specified by the EDITOR or VISUAL environment variables).

After the user completes editing and saves the temporary files, vigr performs essential syntax checks on the modified content to ensure validity. If these checks pass, the temporary files atomically replace the original system files, and the locks are released. This meticulous process guarantees that the group database remains consistent, valid, and uncorrupted, which is vital for system security and user management. Use of vigr requires superuser (root) privileges.

Editing system configuration files directly without proper tools like vigr can lead to severe system instability or security vulnerabilities.

Incorrect syntax or invalid entries introduced during editing can render the group database unusable, potentially preventing users from logging in or causing other system failures.

Always exercise extreme caution and ensure you understand the changes being made. Requires root privileges to execute.

vigr respects the EDITOR or VISUAL environment variables to determine which text editor to launch. If neither of these variables is set, it defaults to using vi for editing the files.

The command ensures atomicity by implementing a robust file locking mechanism and utilizing temporary files for editing. This prevents race conditions and ensures that either the entire set of changes is successfully applied, or none at all, thus maintaining the integrity of the group database even in the event of system crashes or power failures.

Before committing changes from the temporary files back to the original system files, vigr performs essential syntax checks. This validation step helps to catch common errors or malformed entries that could potentially corrupt the group database or make it unreadable by other system utilities.

The vigr command is an integral part of the shadow-utils suite, which originated from the need to enhance the security of Unix-like systems. This suite was developed to separate sensitive password hashes into a restricted-access /etc/shadow file and group password hashes into /etc/gshadow.

vigr was specifically created as the safe editing utility for these group-related files, mirroring the functionality of vipw for password files. Its design principle emphasizes atomicity, data integrity, and validation when modifying critical system configuration files, reflecting best practices for system administration.

vipw(8), group(5), gshadow(5), groupadd(8), groupmod(8), groupdel(8), grpck(8), passwd(5), shadow(5)