2

I want to copy all contents from one disk to another HDD. I thought the cp command might do the trick.

cp -aR /dev/nvme0n1p1/* /dev/sda1/

/dev/nvme01np1 is the old disk that I want its content to be copied and /dev/sda1 is the new disk. However I got an error saying that /dev/nvme01np1 is not a directory.

6
  • Are the devices that you mentioned mounted somewhere on the system?
    – Kusalananda
    Jun 18, 2018 at 11:15
  • it said that /dev/nvme01np1 is mounted on /run and /dev/sda1 is mounted on /sda1/home/ Jun 18, 2018 at 11:29
  • Whoops, sorry, when I checked the "Disks" application, it said that the nvme01np1 is mounted at filesystem root whilst sda1 is mounted at /disks/local Jun 18, 2018 at 11:35
  • What is your intention to do this? Are you going to replace the old HD with the new one after copy? Jun 18, 2018 at 12:02
  • Copying files from the currently running system to another disk is problematic. Better use a live usb. But if you want to make a full copy of partitions/hard drives, it's better to use dd (also from live system) which copies blocks instead of files.
    – pLumo
    Jun 18, 2018 at 13:19

5 Answers 5

7

It depends what you’re trying to do.

Using dd is good for cloning disks. This operates at the block level, low level.

If you are making a backup, rsync is sufficient. It operates at the file system level, above block device level.

If the disks are already mounted (eg have another directory not in the /dev directory), using the rsync command is the recommended way. If you have gigabytes to transfer, rsync is handy because if the process is interrupted, it can restart at the point it was up to.

If there’s hundreds of thousands of files the file list may be too long and it errors. I’ve overcome this by batching the rsync job into subdirectories at a time.

rsync —-avz —-show-progress /path/of/source /path/of/target

Rsync can be used across a network or web securely with ssh and ssh keys and scheduled using the system cron. It’s a handy tool to know.

rsync -e “ssh -i $HOME/.ssh/id_rsa” —-avz —-show-progress /path/of/source user@host:/path/of/target

More info

1
  • I want to copy the Alpine Linux untared image alpine-rpi-*-armhf.tar.gz to the first sd card partition - p0 that is mounted to /home/tim/boot. Can I use cp here? dd does not work as it cannot copy normal files, just devices?
    – Timo
    Oct 23, 2021 at 19:11
1

Copying files from the currently running system to another disk is problematic. You should better use a live system. But with cp you cannot copy devices from /dev, you can only copy between the mount points of the devices.

If you want to clone a partition or hard drive, it's better to use dd which copies blocks instead of files.


  1. Make sure, the second hard drive has at least the same size as the first one.

  2. Startup a live system

  3. Copy hard drive, e.g.:

    dd if=/dev/nvme0n1p of=/dev/sda bs=32M
    

    or using cat (via):

    cat /dev/nvme0n1p >/dev/sda
    

Read:

0

The cp command would only worked if you had tried it on already mounted devices. You could run the exact by using the mounting points of those devices.

cp -aR /path/to/mount/point/of/dev/nvme0n1p1/* /path/to/mount/point/of/dev/sda1/

Usually you could find the mount points either by running mount or df -h. Of coursee dd is your friend when it comes to actually clone one device to an other (faster too). Also please note that most of the folders under the /dev are special folders, kind of devices folders, if that makes any sense.

0

You have to copy from one mountpoint to another. Instead of

cp -aR /dev/nvme0n1p1/* /dev/sda1/

your should do

cp -aR /run/* /sda1/home

because you mounted disk 1 at /run/ and disk 2 at /sda1/home if I understand you correctly.

0

If you are using version 2.6.9 of rsync, plz use this:

rsync -avz --progress /path/of/source /path/of/target

More info about rsync:

rsync --help
rsync  version 2.6.9  protocol version 29
Copyright (C) 1996-2006 by Andrew Tridgell, Wayne Davison, and others.
<http://rsync.samba.org/>
Capabilities: 64-bit files, socketpairs, hard links, symlinks, batchfiles,
              inplace, IPv6, 64-bit system inums, 64-bit internal inums

rsync comes with ABSOLUTELY NO WARRANTY.  This is free software, and you
are welcome to redistribute it under certain conditions.  See the GNU
General Public Licence for details.

rsync is a file transfer program capable of efficient remote update
via a fast differencing algorithm.

Usage: rsync [OPTION]... SRC [SRC]... DEST
  or   rsync [OPTION]... SRC [SRC]... [USER@]HOST:DEST
  or   rsync [OPTION]... SRC [SRC]... [USER@]HOST::DEST
  or   rsync [OPTION]... SRC [SRC]... rsync://[USER@]HOST[:PORT]/DEST
  or   rsync [OPTION]... [USER@]HOST:SRC [DEST]
  or   rsync [OPTION]... [USER@]HOST::SRC [DEST]
  or   rsync [OPTION]... rsync://[USER@]HOST[:PORT]/SRC [DEST]
The ':' usages connect via remote shell, while '::' & 'rsync://' usages connect
to an rsync daemon, and require SRC or DEST to start with a module name.

Options
 -v, --verbose               increase verbosity
 -q, --quiet                 suppress non-error messages
     --no-motd               suppress daemon-mode MOTD (see manpage caveat)
 -c, --checksum              skip based on checksum, not mod-time & size
 -a, --archive               archive mode; same as -rlptgoD (no -H)
     --no-OPTION             turn off an implied OPTION (e.g. --no-D)
 -r, --recursive             recurse into directories
 -R, --relative              use relative path names
     --no-implied-dirs       don't send implied dirs with --relative
 -b, --backup                make backups (see --suffix & --backup-dir)
     --backup-dir=DIR        make backups into hierarchy based in DIR
     --suffix=SUFFIX         set backup suffix (default ~ w/o --backup-dir)
 -u, --update                skip files that are newer on the receiver
     --inplace               update destination files in-place (SEE MAN PAGE)
     --append                append data onto shorter files
 -d, --dirs                  transfer directories without recursing
 -l, --links                 copy symlinks as symlinks
 -L, --copy-links            transform symlink into referent file/dir
     --copy-unsafe-links     only "unsafe" symlinks are transformed
     --safe-links            ignore symlinks that point outside the source tree
 -k, --copy-dirlinks         transform symlink to a dir into referent dir
 -K, --keep-dirlinks         treat symlinked dir on receiver as dir
 -H, --hard-links            preserve hard links
 -p, --perms                 preserve permissions
     --executability         preserve the file's executability
     --chmod=CHMOD           affect file and/or directory permissions
 -o, --owner                 preserve owner (super-user only)
 -g, --group                 preserve group
     --devices               preserve device files (super-user only)
     --specials              preserve special files
 -D                          same as --devices --specials
 -t, --times                 preserve times
 -O, --omit-dir-times        omit directories when preserving times
     --super                 receiver attempts super-user activities
 -S, --sparse                handle sparse files efficiently
 -n, --dry-run               show what would have been transferred
 -W, --whole-file            copy files whole (without rsync algorithm)
 -x, --one-file-system       don't cross filesystem boundaries
 -B, --block-size=SIZE       force a fixed checksum block-size
 -e, --rsh=COMMAND           specify the remote shell to use
     --rsync-path=PROGRAM    specify the rsync to run on the remote machine
     --existing              skip creating new files on receiver
     --ignore-existing       skip updating files that already exist on receiver
     --remove-source-files   sender removes synchronized files (non-dirs)
     --del                   an alias for --delete-during
     --delete                delete extraneous files from destination dirs
     --delete-before         receiver deletes before transfer (default)
     --delete-during         receiver deletes during transfer, not before
     --delete-after          receiver deletes after transfer, not before
     --delete-excluded       also delete excluded files from destination dirs
     --ignore-errors         delete even if there are I/O errors
     --force                 force deletion of directories even if not empty
     --max-delete=NUM        don't delete more than NUM files
     --max-size=SIZE         don't transfer any file larger than SIZE
     --min-size=SIZE         don't transfer any file smaller than SIZE
     --partial               keep partially transferred files
     --partial-dir=DIR       put a partially transferred file into DIR
     --delay-updates         put all updated files into place at transfer's end
 -m, --prune-empty-dirs      prune empty directory chains from the file-list
     --numeric-ids           don't map uid/gid values by user/group name
     --timeout=TIME          set I/O timeout in seconds
 -I, --ignore-times          don't skip files that match in size and mod-time
     --size-only             skip files that match in size
     --modify-window=NUM     compare mod-times with reduced accuracy
 -T, --temp-dir=DIR          create temporary files in directory DIR
 -y, --fuzzy                 find similar file for basis if no dest file
     --compare-dest=DIR      also compare destination files relative to DIR
     --copy-dest=DIR         ... and include copies of unchanged files
     --link-dest=DIR         hardlink to files in DIR when unchanged
 -z, --compress              compress file data during the transfer
     --compress-level=NUM    explicitly set compression level
 -C, --cvs-exclude           auto-ignore files the same way CVS does
 -f, --filter=RULE           add a file-filtering RULE
 -F                          same as --filter='dir-merge /.rsync-filter'
                             repeated: --filter='- .rsync-filter'
     --exclude=PATTERN       exclude files matching PATTERN
     --exclude-from=FILE     read exclude patterns from FILE
     --include=PATTERN       don't exclude files matching PATTERN
     --include-from=FILE     read include patterns from FILE
     --files-from=FILE       read list of source-file names from FILE
 -0, --from0                 all *-from/filter files are delimited by 0s
     --address=ADDRESS       bind address for outgoing socket to daemon
     --port=PORT             specify double-colon alternate port number
     --sockopts=OPTIONS      specify custom TCP options
     --blocking-io           use blocking I/O for the remote shell
     --stats                 give some file-transfer stats
 -8, --8-bit-output          leave high-bit chars unescaped in output
 -h, --human-readable        output numbers in a human-readable format
     --progress              show progress during transfer
 -P                          same as --partial --progress
 -i, --itemize-changes       output a change-summary for all updates
     --out-format=FORMAT     output updates using the specified FORMAT
     --log-file=FILE         log what we're doing to the specified FILE
     --log-file-format=FMT   log updates using the specified FMT
     --password-file=FILE    read password from FILE
     --list-only             list the files instead of copying them
     --bwlimit=KBPS          limit I/O bandwidth; KBytes per second
     --write-batch=FILE      write a batched update to FILE
     --only-write-batch=FILE like --write-batch but w/o updating destination
     --read-batch=FILE       read a batched update from FILE
     --protocol=NUM          force an older protocol version to be used
 -E, --extended-attributes   copy extended attributes
     --cache                 disable fcntl(F_NOCACHE)
 -4, --ipv4                  prefer IPv4
 -6, --ipv6                  prefer IPv6
     --version               print version number
(-h) --help                  show this help (-h works with no other options)

Use "rsync --daemon --help" to see the daemon-mode command-line options.
Please see the rsync(1) and rsyncd.conf(5) man pages for full documentation.
See http://rsync.samba.org/ for updates, bug reports, and answers
1
  • This answer in correct in general, but not specific to the question being asked.
    – U. Windl
    Feb 3 at 22:52

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