tar

tar

The tar command in Unix and Linux is a versatile utility used for creating and manipulating archive files. It stands for "tape archive," as it was originally used for archiving files onto magnetic tape. Today, tar is commonly used to package files and directories into a single file, often compressed, for easier storage, distribution, and backup.

Basic Usage

The basic syntax for the tar command is:

tar [options] [archive-file] [file(s) or directory(s)]

• options: Optional command-line options to control the behavior of tar.

• archive-file: The name of the archive file to create or manipulate.

• file(s) or directory(s): The file(s) or directory(s) to include in the archive.

Examples

Creating an Archive

To create a new archive file:

tar -cvf archive.tar file1.txt file2.txt directory/

• -c: Create a new archive.

• -v: Verbose mode (show progress).

• -f archive.tar: Specify the archive file name (archive.tar in this case).

• file1.txt file2.txt directory/: List of files and directories to include in the archive.

This command creates a new archive named archive.tar containing file1.txt, file2.txt, and the contents of directory/.

Extracting from an Archive

To extract files from an archive:

tar -xvf archive.tar

• -x: Extract files from an archive.

• -v: Verbose mode (show progress).

• -f archive.tar: Specify the archive file name (archive.tar in this case).

This command extracts the contents of archive.tar to the current directory.

Compressing an Archive

To compress an archive using gzip:

tar -cvzf archive.tar.gz directory/

• -z: Compress the archive using gzip.

• -f archive.tar.gz: Specify the gzip-compressed archive file name (archive.tar.gz in this case).

• -c: Create a new archive.

• -v: Verbose mode (show progress).

This command creates a gzip-compressed archive named archive.tar.gz containing the contents of directory/.

Options

Compression Options

• -z: Compress the archive using gzip.

• -j: Compress the archive using bzip2.

• -J: Compress the archive using xz.

Archive Manipulation

• -c: Create a new archive.

• -x: Extract files from an archive.

• -t: List the contents of an archive.

• -r: Append files to an archive.

File and Directory Options

• -f archive-file: Specify the archive file name.

• -v: Verbose mode (show progress).

• -C directory: Change to the specified directory before performing operations.

Practical Use Cases

Backup and Restore

To create a backup of important files and directories:

tar -cvzf backup.tar.gz /home/user/documents

This command creates a compressed backup (backup.tar.gz) of the documents directory.

Distributing Software Packages

To package software files for distribution:

tar -cvf software.tar.gz software/

This command creates a compressed archive (software.tar.gz) of the software/ directory for distribution.

Archiving and Compression

To archive and compress multiple directories into one file:

tar -cvzf archive.tar.gz directory1/ directory2/

This command creates a gzip-compressed archive (archive.tar.gz) containing directory1/ and directory2/.

Summary

The tar command is essential for creating, manipulating, and extracting archive files in Unix and Linux systems. Its flexibility with options allows for various operations such as creating, extracting, compressing, appending files, and more. Understanding these options and their applications can greatly enhance your ability to manage and distribute files efficiently.

help

Usage: tar [OPTION...] [FILE]...
GNU 'tar' saves many files together into a single tape or disk archive, and can
restore individual files from the archive.

Examples:
  tar -cf archive.tar foo bar  # Create archive.tar from files foo and bar.
  tar -tvf archive.tar         # List all files in archive.tar verbosely.
  tar -xf archive.tar          # Extract all files from archive.tar.

 Main operation mode:
  -A, --catenate, --concatenate   append tar files to an archive
  -c, --create               create a new archive
      --delete               delete from the archive (not on mag tapes!)
  -d, --diff, --compare      find differences between archive and file system
  -r, --append               append files to the end of an archive
      --test-label           test the archive volume label and exit
  -t, --list                 list the contents of an archive
  -u, --update               only append files newer than copy in archive
  -x, --extract, --get       extract files from an archive

 Operation modifiers:

      --check-device         check device numbers when creating incremental
                             archives (default)
  -g, --listed-incremental=FILE   handle new GNU-format incremental backup
  -G, --incremental          handle old GNU-format incremental backup
      --hole-detection=TYPE  technique to detect holes
      --ignore-failed-read   do not exit with nonzero on unreadable files
      --level=NUMBER         dump level for created listed-incremental archive
      --no-check-device      do not check device numbers when creating
                             incremental archives
      --no-seek              archive is not seekable
  -n, --seek                 archive is seekable
      --occurrence[=NUMBER]  process only the NUMBERth occurrence of each file
                             in the archive; this option is valid only in
                             conjunction with one of the subcommands --delete,
                             --diff, --extract or --list and when a list of
                             files is given either on the command line or via
                             the -T option; NUMBER defaults to 1
      --sparse-version=MAJOR[.MINOR]
                             set version of the sparse format to use (implies
                             --sparse)
  -S, --sparse               handle sparse files efficiently

 Local file name selection:
      --add-file=FILE        add given FILE to the archive (useful if its name
                             starts with a dash)
  -C, --directory=DIR        change to directory DIR
      --exclude=PATTERN      exclude files, given as a PATTERN
      --exclude-backups      exclude backup and lock files
      --exclude-caches       exclude contents of directories containing
                             CACHEDIR.TAG, except for the tag file itself
      --exclude-caches-all   exclude directories containing CACHEDIR.TAG
      --exclude-caches-under exclude everything under directories containing
                             CACHEDIR.TAG
      --exclude-ignore=FILE  read exclude patterns for each directory from
                             FILE, if it exists
      --exclude-ignore-recursive=FILE
                             read exclude patterns for each directory and its
                             subdirectories from FILE, if it exists
      --exclude-tag=FILE     exclude contents of directories containing FILE,
                             except for FILE itself
      --exclude-tag-all=FILE exclude directories containing FILE
      --exclude-tag-under=FILE   exclude everything under directories
                             containing FILE
      --exclude-vcs          exclude version control system directories
      --exclude-vcs-ignores  read exclude patterns from the VCS ignore files
      --no-null              disable the effect of the previous --null option
      --no-recursion         avoid descending automatically in directories
      --no-unquote           do not unquote input file or member names
      --no-verbatim-files-from   -T treats file names starting with dash as
                             options (default)
      --null                 -T reads null-terminated names; implies
                             --verbatim-files-from
      --recursion            recurse into directories (default)
  -T, --files-from=FILE      get names to extract or create from FILE
      --unquote              unquote input file or member names (default)
      --verbatim-files-from  -T reads file names verbatim (no escape or option
                             handling)
  -X, --exclude-from=FILE    exclude patterns listed in FILE

 File name matching options (affect both exclude and include patterns):

      --anchored             patterns match file name start
      --ignore-case          ignore case
      --no-anchored          patterns match after any '/' (default for
                             exclusion)
      --no-ignore-case       case sensitive matching (default)
      --no-wildcards         verbatim string matching
      --no-wildcards-match-slash   wildcards do not match '/'
      --wildcards            use wildcards (default for exclusion)
      --wildcards-match-slash   wildcards match '/' (default for exclusion)

 Overwrite control:

      --keep-directory-symlink   preserve existing symlinks to directories when
                             extracting
      --keep-newer-files     don't replace existing files that are newer than
                             their archive copies
  -k, --keep-old-files       don't replace existing files when extracting,
                             treat them as errors
      --no-overwrite-dir     preserve metadata of existing directories
      --one-top-level[=DIR]  create a subdirectory to avoid having loose files
                             extracted
      --overwrite            overwrite existing files when extracting
      --overwrite-dir        overwrite metadata of existing directories when
                             extracting (default)
      --recursive-unlink     empty hierarchies prior to extracting directory
      --remove-files         remove files after adding them to the archive
      --skip-old-files       don't replace existing files when extracting,
                             silently skip over them
  -U, --unlink-first         remove each file prior to extracting over it
  -W, --verify               attempt to verify the archive after writing it

 Select output stream:

      --ignore-command-error ignore exit codes of children
      --no-ignore-command-error   treat non-zero exit codes of children as
                             error
  -O, --to-stdout            extract files to standard output
      --to-command=COMMAND   pipe extracted files to another program

 Handling of file attributes:

      --atime-preserve[=METHOD]   preserve access times on dumped files, either
                             by restoring the times after reading
                             (METHOD='replace'; default) or by not setting the
                             times in the first place (METHOD='system')
      --clamp-mtime          only set time when the file is more recent than
                             what was given with --mtime
      --delay-directory-restore   delay setting modification times and
                             permissions of extracted directories until the end
                             of extraction
      --group=NAME           force NAME as group for added files
      --group-map=FILE       use FILE to map file owner GIDs and names
      --mode=CHANGES         force (symbolic) mode CHANGES for added files
      --mtime=DATE-OR-FILE   set mtime for added files from DATE-OR-FILE
  -m, --touch                don't extract file modified time
      --no-delay-directory-restore
                             cancel the effect of --delay-directory-restore
                             option
      --no-same-owner        extract files as yourself (default for ordinary
                             users)
      --no-same-permissions  apply the user's umask when extracting permissions
                             from the archive (default for ordinary users)
      --numeric-owner        always use numbers for user/group names
      --owner=NAME           force NAME as owner for added files
      --owner-map=FILE       use FILE to map file owner UIDs and names
  -p, --preserve-permissions, --same-permissions
                             extract information about file permissions
                             (default for superuser)
      --same-owner           try extracting files with the same ownership as
                             exists in the archive (default for superuser)
      --sort=ORDER           directory sorting order: none (default), name or
                             inode
  -s, --preserve-order, --same-order
                             member arguments are listed in the same order as
                             the files in the archive

 Handling of extended file attributes:

      --acls                 Enable the POSIX ACLs support
      --no-acls              Disable the POSIX ACLs support
      --no-selinux           Disable the SELinux context support
      --no-xattrs            Disable extended attributes support
      --selinux              Enable the SELinux context support
      --xattrs               Enable extended attributes support
      --xattrs-exclude=MASK  specify the exclude pattern for xattr keys
      --xattrs-include=MASK  specify the include pattern for xattr keys

 Device selection and switching:

      --force-local          archive file is local even if it has a colon
  -f, --file=ARCHIVE         use archive file or device ARCHIVE
  -F, --info-script=NAME, --new-volume-script=NAME
                             run script at end of each tape (implies -M)
  -L, --tape-length=NUMBER   change tape after writing NUMBER x 1024 bytes
  -M, --multi-volume         create/list/extract multi-volume archive
      --rmt-command=COMMAND  use given rmt COMMAND instead of rmt
      --rsh-command=COMMAND  use remote COMMAND instead of rsh
      --volno-file=FILE      use/update the volume number in FILE

 Device blocking:

  -b, --blocking-factor=BLOCKS   BLOCKS x 512 bytes per record
  -B, --read-full-records    reblock as we read (for 4.2BSD pipes)
  -i, --ignore-zeros         ignore zeroed blocks in archive (means EOF)
      --record-size=NUMBER   NUMBER of bytes per record, multiple of 512

 Archive format selection:

  -H, --format=FORMAT        create archive of the given format

 FORMAT is one of the following:
    gnu                      GNU tar 1.13.x format
    oldgnu                   GNU format as per tar <= 1.12
    pax                      POSIX 1003.1-2001 (pax) format
    posix                    same as pax
    ustar                    POSIX 1003.1-1988 (ustar) format
    v7                       old V7 tar format

      --old-archive, --portability
                             same as --format=v7
      --pax-option=keyword[[:]=value][,keyword[[:]=value]]...
                             control pax keywords
      --posix                same as --format=posix
  -V, --label=TEXT           create archive with volume name TEXT; at
                             list/extract time, use TEXT as a globbing pattern
                             for volume name

 Compression options:

  -a, --auto-compress        use archive suffix to determine the compression
                             program
  -I, --use-compress-program=PROG
                             filter through PROG (must accept -d)
  -j, --bzip2                filter the archive through bzip2
  -J, --xz                   filter the archive through xz
      --lzip                 filter the archive through lzip
      --lzma                 filter the archive through xz
      --lzop                 filter the archive through lzop
      --no-auto-compress     do not use archive suffix to determine the
                             compression program
      --zstd                 filter the archive through zstd
  -z, --gzip, --gunzip, --ungzip   filter the archive through gzip
  -Z, --compress, --uncompress   filter the archive through compress

 Local file selection:

      --backup[=CONTROL]     backup before removal, choose version CONTROL
      --hard-dereference     follow hard links; archive and dump the files they
                             refer to
  -h, --dereference          follow symlinks; archive and dump the files they
                             point to
  -K, --starting-file=MEMBER-NAME
                             begin at member MEMBER-NAME when reading the
                             archive
      --newer-mtime=DATE     compare date and time when data changed only
  -N, --newer=DATE-OR-FILE, --after-date=DATE-OR-FILE
                             only store files newer than DATE-OR-FILE
      --one-file-system      stay in local file system when creating archive
  -P, --absolute-names       don't strip leading '/'s from file names
      --suffix=STRING        backup before removal, override usual suffix ('~'
                             unless overridden by environment variable
                             SIMPLE_BACKUP_SUFFIX)

 File name transformations:

      --strip-components=NUMBER   strip NUMBER leading components from file
                             names on extraction
      --transform=EXPRESSION, --xform=EXPRESSION
                             use sed replace EXPRESSION to transform file
                             names

 Informative output:

      --checkpoint[=NUMBER]  display progress messages every NUMBERth record
                             (default 10)
      --checkpoint-action=ACTION   execute ACTION on each checkpoint
      --full-time            print file time to its full resolution
      --index-file=FILE      send verbose output to FILE
  -l, --check-links          print a message if not all links are dumped
      --no-quote-chars=STRING   disable quoting for characters from STRING
      --quote-chars=STRING   additionally quote characters from STRING
      --quoting-style=STYLE  set name quoting style; see below for valid STYLE
                             values
  -R, --block-number         show block number within archive with each message
                            
      --show-defaults        show tar defaults
      --show-omitted-dirs    when listing or extracting, list each directory
                             that does not match search criteria
      --show-snapshot-field-ranges
                             show valid ranges for snapshot-file fields
      --show-transformed-names, --show-stored-names
                             show file or archive names after transformation
      --totals[=SIGNAL]      print total bytes after processing the archive;
                             with an argument - print total bytes when this
                             SIGNAL is delivered; Allowed signals are: SIGHUP,
                             SIGQUIT, SIGINT, SIGUSR1 and SIGUSR2; the names
                             without SIG prefix are also accepted
      --utc                  print file modification times in UTC
  -v, --verbose              verbosely list files processed
      --warning=KEYWORD      warning control
  -w, --interactive, --confirmation
                             ask for confirmation for every action

 Compatibility options:

  -o                         when creating, same as --old-archive; when
                             extracting, same as --no-same-owner

 Other options:

  -?, --help                 give this help list
      --restrict             disable use of some potentially harmful options
      --usage                give a short usage message
      --version              print program version

Mandatory or optional arguments to long options are also mandatory or optional
for any corresponding short options.

The backup suffix is '~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX.
The version control may be set with --backup or VERSION_CONTROL, values are:

  none, off       never make backups
  t, numbered     make numbered backups
  nil, existing   numbered if numbered backups exist, simple otherwise
  never, simple   always make simple backups