cpio.h - Linux

Overview

cpio is a command-line utility for creating, extracting, or manipulating compressed or uncompressed cpio archives. It’s commonly used to backup or transfer files between systems.

Syntax

cpio [-abcdfilmnopuvz] [-A archive] [-B blocksize] [files...]

Options/Flags

  • -a: Append specified files to an existing archive.
  • -b: Swap the bytes in each word for portability across architectures.
  • -c: Create a new cpio archive.
  • -d: Extract files from an archive.
  • -f: Specify the archive file to operate on.
  • -i: Read files from standard input to create an archive.
  • -l: List the contents of an archive.
  • -m: Preserve file modification timestamps.
  • -n: Never create the archive even if it doesn’t exist.
  • -o: Extract files to standard output.
  • -p: Preserve file permissions.
  • -u: Update existing files in the archive if they’re newer than their archive counterparts.
  • -v: Print verbose information during operation.
  • -z: Compress/decompress the archive using gzip.

Examples

Creating an archive:

cpio -cvf archive.cpio files...

Extracting an archive:

cpio -idvf archive.cpio

Updating an archive:

cpio -umv archive.cpio updated_files...

Common Issues

  • Ensure that the archive file exists before trying to extract files.
  • Use the -v option to troubleshoot extraction or creation issues.
  • If creating an archive with compression, ensure the required compression tool (gzip or others) is installed.

Integration

cpio can be integrated with other commands, such as:

  • tar: Convert cpio archives to tar archives:

    cpio -iv archive.cpio | tar -xvf -

  • find: Create an archive of specific files:

    find . -name '*.txt' -exec cpio -vo archive.cpio -- {} +

Related Commands

  • tar: Archive and compress files.
  • gzip: Compress files.
  • bzip2: Compress files.
  • 7z: Archive and compress files.