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Linux Command Manual

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Linux cpio command

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The Linux cpio command is used for backing up files.

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cpio is a utility program used to create and restore backup archives. It can add, extract, or list files within cpio or tar backup archives.

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Syntax

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\ncpio [-C <Input/Output Size>][-F <Archive>][-H <Archive Format>][-O <Archive>][--block-size=<Block Size>]\nor\ncpio [-C <Input/Output Size>][-E <Pattern File>][-F <Archive>][-H <Archive Format>][-I <Archive>][-M <Message>][-R <Owner><:/.><Group>][--block-size=<Block Size>][Pattern...]\nor\ncpio [-R <Owner><:/.><Group>]\n

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Parameters:

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• -0 or --null: Accepts new line control characters, typically used with the "-print0" parameter of the find command.
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• -a or --reset-access-time: Resets the access time of files.
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• -A or --append: Appends to an existing archive. The archive must reside on disk, not on a tape drive.
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• -b or --swap: The effect of this parameter is the same as specifying both "-sS" parameters.
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• -B: Sets the input/output block size to 5120 Bytes.
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• -c: Uses the old ASCII backup format.
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• -C<Block Size> or --io-size=<Block Size>: Sets the input/output block size in Bytes.
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• -d or --make-directories: Creates directories as needed.
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• -E<Pattern File> or --pattern-file=<Pattern File>: Specifies a pattern file containing one or more patterns, allowing cpio to extract files matching the pattern conditions. The format is one pattern per line.
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• -f or --nonmatching: Makes cpio extract all files that do NOT match the pattern conditions.
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• -F<Archive> or --file=<Archive>: Specifies the archive name to use instead of standard input or output, allowing access to archives on another host's storage device over the network.
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• -H<Archive Format>: Specifies the file format to use during backup.
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• -i or --extract: Executes copy-in mode, restoring the backup archive.
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• -I<Archive>: Specifies the archive name to use instead of standard input, allowing reading archives from another host's storage device over the network.
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• -k: This parameter is ignored and only handles compatibility issues between different cpio versions.
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• -l or --link: Creates hard links instead of copying files; can be used in copy-pass mode.
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• -L or --dereference: Does not create symbolic links; directly copies the original file that the link points to.
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• -m or --preserve-modification-time: Does not change the modification time of files.
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• -M<Message> or --message=<Message>: Sets the message for changing storage media.
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• -n or --numeric-uid-gid: When listing archive contents with the "-tv" parameter, adding "-n" will list files using user ID and group ID instead of owner and group names.
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• -o or --create: Executes copy-out mode, creating a backup archive.
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• -O<Archive>: Specifies the archive name to use instead of standard output, allowing storage on another host's storage device over the network.
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• -p or --pass-through: Executes copy-pass mode, skipping the backup step and directly copying files to the destination directory.
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• -r or --rename: Uses interactive mode when filenames need to be changed.
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• -R<Owner><:/.><Group> or --owner<Owner><:/.><Group>: In copy-in mode when restoring archives, or copy-pass mode when copying files, this specifies the owner and group for the restored/copied files.
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• -s or --swap-bytes: Swaps the contents of each pair of bytes.
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• -S or --swap-halfwords: Swaps the contents of each halfword (2 bytes).
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• -t or --list: Lists the input contents.
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• -u or --unconditional: Replaces all files unconditionally, regardless of date/time, overwriting without asking.
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• -v or --verbose: Displays the execution process of the command in detail.
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• -V or --dot: Adds a "." before each file during command execution.
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• --block-size=<Block Size>: Sets the input/output block size. If set to 5, block size is 2500; if set to 10, block size is 5120, and so on.
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• --force-local: Forces the archive to be stored on the local host.
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• --help: Displays online help.
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• --no-absolute-filenames: Uses relative paths to create filenames.
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• --no-preserve-owner: Does not preserve the file owner; whoever extracts the archive owns the files.
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• --only-verify-crc: When the archive uses the CRC backup format, this parameter checks whether each file in the archive is correct.
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• --quiet: Does not display how many blocks were copied.
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• --sparse: If a file contains many consecutive zero bytes, stores it as a sparse file.
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• --version: Displays version information.
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Examples

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Create a backup file:

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\n[root@.com var]# ll //List files in current directory\ntotal 164\ndrwxr-xr-x 2 root root 4096 2008-03-30 account\ndrwxr-xr-x 9 root root 4096 2008-03-30 cache\ndrwxr-xr-x 3 netdump netdump 4096 2008-03-30 crash\ndrwxr-xr-x 3 root root 4096 2008-03-30 db\ndrwxr-xr-x 3 root root 4096 2008-03-30 empty\ndrwxr-xr-x 3 root root 4096 2008-03-30 ftp\ndrwxrwx--T 2 root gdm 4096 Apr  9 20:17 gdm\ndrwxr-xr-x 25 root root 4096 2008-03-30 lib\ndrwxr-xr-x 2 root root 4096 2004-08-13 local\ndrwxrwxr-x 6 root lock 4096 May  8 15:25 lock\ndrwxr-xr-x 14 root root 4096 May  8 15:14 log\nlrwxrwxrwx 1 root root   10 2008-03-30 mail -> spool/mail\ndrwxr-xr-x 2 root root 4096 2004-08-13 nis\ndrwxr-xr-x 2 root root 4096 2004-08-13 opt\ndrwxr-xr-x 2 root root 4096 2004-08-13 preserve\ndrwxr-xr-x 16 root root 4096 May  8 15:14 run\ndrwxr-xr-x 16 root root 4096 2008-03-30 spool\ndrwxrwxrwt 3 root root 4096 Jan 13 18:53 tmp\ndrwx------ 2 root root 4096 2004-07-08 tux\ndrwxr-xr-x 8 root root 4096 Jan 19 19:39 www\ndrwxr-xr-x 3 root root 4096 2008-03-30 yp\n[root@.com var]# ls | cpio -o >123.cpio //Create backup file\n25 blocks\n[root@.com var]# ll //List files in current directory\ntotal 172\n-rw-r--r-- 1 root root 1024 May 24 13:06 123.cpio\ndrwxr-xr-x 2 root root 4096 2008-03-30 account\ndrwxr-xr-x 9 root root 4096 2008-03-30 cache\ndrwxr-xr-x 3 netdump netdump 4096 2008-03-30 crash\ndrwxr-xr-x 3 root root 4096 2008-03-30 db\ndrwxr-xr-x 3 root root 4096 2008-03-30 empty\ndrwxr-xr-x 3 root root 4096 2008-03-30 ftp\ndrwxrwx--T 2 root gdm 4096 Apr  9 20:17 gdm\ndrwxr-xr-x 25 root root 4096 2008-03-30 lib\ndrwxr-xr-x 2 root root 4096 2004-08-13 local\ndrwxrwxr-x 6 root lock 4096 May  8 15:25 lock\ndrwxr-xr-x 14 root root 4096 May  8 15:14 log\nlrwxrwxrwx 1 root root   10 2008-03-30 mail -> spool/mail\ndrwxr-xr-x 2 root root 4096 2004-08-13 nis\ndrwxr-xr-x 2 root root 4096 2004-08-13 opt\ndrwxr-xr-x 2 root root 4096 2004-08-13 preserve\ndrwxr-xr-x 16 root root 4096 May  8 15:14 run\ndrwxr-xr-x 16 root root 4096 2008-03-30 spool\ndrwxrwxrwt 3 root root 4096 Jan 13 18:53 tmp\ndrwx------ 2 root root 4096 2004-07-08 tux\ndrwxr-xr-x 8 root root 4096 Jan 19 19:39 www\ndrwxr-xr-x 3 root root 4096 2008-03-30 yp\n[root@.com var]#\n

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Extract a backup file:

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\n[root@.com var]# ls | cpio -i -l 123.cpio\n

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Extract backup file and list detailed information:

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\n[root@.com var]# cpio -t -I 123.cpio\n123.cpio\na.c\nb.c\nc.c\n……Partial results omitted\n

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Force extraction:

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\n[root@.com var]# cpio -i -u -I 123.cpio\n

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Perform reverse matching during extraction, specify files not to extract:

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\n[root@.com var]# cpio -i -I 123.cpio -f *.c //Do not extract files ending with .c\n

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Add files to a specified .cpio file:

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\n[root@.com var]# ls\n123.cpio crash ftp local mail preserve tmp yp\naccount db gdm lock nis run tux cache empty lib log opt spool www\n[root@.com var]# cpio -o -O 123.cpio -A db //User input, press Ctrl+D to end\n1 block\n[root@.com var]#\n

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Backup files from standard input:

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\n[root@.com test]# ls\na. a.c b.c c.c d.c f.c\n[root@.com test]# cpio -o >123.cpio\na.c //User input\nb.c\nc.c //Press Ctrl+D to complete input\n3 block\n[root@.com test]#\n

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Copy files:

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\n[root@.com test]# cpio -p /root\na.c //User input\nb.c\nc.c //Press Ctrl+D to complete input\n3 block\n

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Linux Command Manual