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🔄 e2undo(8) — System Manager's Manual

📝 NAME

e2undo — Replay an undo log for an ext2/ext3/ext4 file system

🚀 Quick Reference

Use Case	Command	Description
🔄 Undo a failed operation	e2undo undo_log device	Replay the undo log to revert changes
🔓 Force undo (bypass signature check)	e2undo -f undo_log device	Apply undo even if superblock signature doesn't match
🧪 Dry‑run (preview only)	e2undo -n undo_log device	Show what would be done without writing any blocks
📏 Specify filesystem offset	e2undo -o offset undo_log device	Set the offset (in bytes) from the beginning of the device
📢 Verbose mode	e2undo -v undo_log device	Report which block is currently being replayed
💾 Create an undo file before overwriting	e2undo -z undo_file undo_log device	Save current block contents so they can be restored later

📖 SYNOPSIS

e2undo [ -f ] [ -h ] [ -n ] [ -o offset ] [ -v ] [ -z undo_file ] undo_log device

📝 DESCRIPTION

e2undo will replay the undo log undo_log for an ext2/ext3/ext4 file system found on device. This can be used to undo a failed operation by an e2fsprogs program.

⚙️ OPTIONS

🔒 -f

Normally, e2undo will check the file system superblock to make sure the undo log matches with the file system on the device. If they do not match, e2undo will refuse to apply the undo log as a safety mechanism. The -f option disables this safety mechanism.

ℹ️ -h

Display a usage message.

🧪 -n

Dry‑run; do not actually write blocks back to the file system.

📏 -o offset

Specify the file system's offset (in bytes) from the beginning of the device or file.

📢 -v

Report which block we're currently replaying.

💾 -z undo_file

Before overwriting a file system block, write the old contents of the block to an undo file. This undo file can be used with e2undo(8) to restore the old contents of the file system should something go wrong. If the empty string is passed as the undo_file argument, the undo file will be written to a file named e2undo-device.e2undo in the directory specified via the E2FSPROGS_UNDO_DIR environment variable.

⚠️ WARNING: The undo file cannot be used to recover from a power or system crash.

👤 AUTHOR

e2undo was written by Aneesh Kumar K.V. (aneesh.kumar AT linux.com)

📦 AVAILABILITY

e2undo is part of the e2fsprogs package and is available from http://e2fsprogs.sourceforge.net.

🔗 SEE ALSO

mke2fs(8), tune2fs(8)

E2fsprogs version 1.46.5 — December 2021 — E2UNDO(8)

🔄 e2undo(8) — System Manager's Manual 📝 NAME 🚀 Quick Reference 📖 SYNOPSIS 📝 DESCRIPTION ⚙️ OPTIONS 👤 AUTHOR 📦 AVAILABILITY 🔗 SEE ALSO