8 ms·

> rsync is not a replacement [...] I can't use cp like syntax, it's not a replacement. Can you explain what you mean by this? I use rsync with the 'same synta

> rsync is not a replacement [...] I can't use cp like syntax, it's not a replacement. Can you explain what you mean by this? I use rsync with the 'same syntax'; instead of 'scp src user@remote:/dst' I can do 'rsync src user@remote:/dst'

jacobush 6y ago
Rsync has weird syntax, I have accidentally copied contents of dirs instead of the dir
- mhalle 6y ago
  Rsync has "weird" syntax for a reason. Unlike other unix-like commands, it treats trailing slashes as significant. If a directory has a trailing slash, it means "contents" of the directory". No slash means "the directory itself". These are two different concepts, and a program that copies directories should take the difference into account. scp (and cp, for that matter) don't take this difference into account. That leads to gotchas with recursive (-r) copying. Most importantly, scp isn't idemopotent: scp -r fromdir todir If todir doesn't exist, scp will copy the contents of directory fromdir to a new directory named todir. Execute the same command again (now that todir exists), and scp will copy fromdir to todir/fromdir . On the other hand: rsync -a fromdir/ todir will always copy the contents of fromdir into a directory named todir (effectively, a directory rename operation), whether todir exists or not. rsync -a fromdir todir will always copy the directory fromdir into the directory todir, whether todir exists or not. These rsync operations are idempotent, which it important because rsync is designed to incrementally re-sync directories. It is expected that it will commonly be run more than once, which is why it needed to address this IMHO fundamental bug/limitation in cp and scp.
  - WanderPanda 6y ago
    Thanks for the concise clarification! I always was too lazy to think and did trial and error until it did the thing I intended :)
  - Buttons840 6y ago
    What does rsync'ing "the directory itself" (in contrast to the directory content) even do? A mkdir? Does it even need to use the network connection?
    - 411111111111111 6y ago
      Rsync only works on directories in recursive mode which also copies the contents
    - mhalle 6y ago
      "Rsyncing the directory itself" means making a copy of the directory node (the root of the tree) and naming it with the original name in the new location. That is different than taking the children of the source directory and copying them into the new location. Scp and cp have the same semantics, so cp is vulberable to this gotcha as well. Rsync doesn't have to be used with remote sources or targets (nor does scp).
      - Izkata 6y ago
        > so cp is vulberable to this gotcha as well This is in fact why use rsync for local copies as well, it's much more consistent.
  - orra 6y ago
    Ah, good explanation. Rsync's command line syntax always felt more intuitive to me, and it being idempotent is part of that.
alias_neo 6y ago
Handling of directories and their contents (trailing slashes) is different.
- stjohnswarts 6y ago
  That tab completion will really get you sometimes :)
pletnes 6y ago
Scp works fine in gitbash, I’ve never found a windows-native rsync.
- steerablesafe 6y ago
  I never had a problem with cygwin rsync.
  - jlokier 6y ago
    It sees the filesystem the way Cygwin maps it, so what's transferred isn't an exact match for Windows files and attributes. For example, Windows symlinks and Cygwin symlinks are quite different. I don't think Cygwin rsync can replicate a directory containing Windows symlinks properly, so that the replica behaves the same as seen by Windows programs. I'm not sure about the other Windows attributes such as ACLs but I would be surprised if Cygwin rsync can replicate those.
    - stjohnswarts 6y ago
      very few things can handle stuff like that going from windows->$another_os. You'll just have to compress them down with a format that understands those and preserves them and transfer it. Some of them don't even make sense on other filesystems.
      - jlokier 6y ago
        That's true. But sometimes you just want to move things from Windows to Windows. Then cygwin rsync isn't up to it. (scp isn't either.) That's different from MacOS, where there's a Mac-native version of rsync to transfer attributes that don't exist on $another_os.
40four 6y ago
Yeah I don’t quite understand that stance either. It seems like a great replacement. Rsync > scp in my opinion. I have always reached for it first.
eznzt 6y ago
rsync has a very restrictive licence.
- kzrdude 6y ago
  As a user-facing program it literally doesn't matter, it's only a political issue. You install it and you use it. The problem is if you're scared of the presence of GPLv3 for no reason.
  - eznzt 6y ago
    It means that for example Mac OS or Windows will not bundle it by default.
    - kzrdude 6y ago
      Because they are scared of the presence of GPLv3 for no reason. Still a good point. Mac OS also doesn't ship modern GCC or Bash, so they are pretty much at war with reality at this point - or rather - creating their own ecosystem.
      - em-bee 6y ago
        every other unix system besides linux used to be like that. for many sysadmins the first action on a new unix server or workstation was to install gnu tools. apple decided to include those tools by default possibly in order to attract users. then they decided to stop updating and now macos is no better than those other unix systems used to be. i used a mac for a few years and i don't miss the experience. gnu/linux just works
    - zeveb 6y ago
      I think that problem is with macOS & Windows, not with rsync. There is no real reason why either cannot bundle it; they just choose not to.
- pabs3 6y ago
  There is openrsync if you don't like the rsync license. https://www.openrsync.org/ https://www.openrsync.org/

jacobush 6y ago

Rsync has weird syntax, I have accidentally copied contents of dirs instead of the dir

mhalle 6y ago
Rsync has "weird" syntax for a reason. Unlike other unix-like commands, it treats trailing slashes as significant. If a directory has a trailing slash, it means "contents" of the directory". No slash means "the directory itself". These are two different concepts, and a program that copies directories should take the difference into account. scp (and cp, for that matter) don't take this difference into account. That leads to gotchas with recursive (-r) copying. Most importantly, scp isn't idemopotent: scp -r fromdir todir If todir doesn't exist, scp will copy the contents of directory fromdir to a new directory named todir. Execute the same command again (now that todir exists), and scp will copy fromdir to todir/fromdir . On the other hand: rsync -a fromdir/ todir will always copy the contents of fromdir into a directory named todir (effectively, a directory rename operation), whether todir exists or not. rsync -a fromdir todir will always copy the directory fromdir into the directory todir, whether todir exists or not. These rsync operations are idempotent, which it important because rsync is designed to incrementally re-sync directories. It is expected that it will commonly be run more than once, which is why it needed to address this IMHO fundamental bug/limitation in cp and scp.
- WanderPanda 6y ago
  Thanks for the concise clarification! I always was too lazy to think and did trial and error until it did the thing I intended :)
- Buttons840 6y ago
  What does rsync'ing "the directory itself" (in contrast to the directory content) even do? A mkdir? Does it even need to use the network connection?
  - 411111111111111 6y ago
    Rsync only works on directories in recursive mode which also copies the contents
  - mhalle 6y ago
    "Rsyncing the directory itself" means making a copy of the directory node (the root of the tree) and naming it with the original name in the new location. That is different than taking the children of the source directory and copying them into the new location. Scp and cp have the same semantics, so cp is vulberable to this gotcha as well. Rsync doesn't have to be used with remote sources or targets (nor does scp).
    - Izkata 6y ago
      > so cp is vulberable to this gotcha as well This is in fact why use rsync for local copies as well, it's much more consistent.
- orra 6y ago
  Ah, good explanation. Rsync's command line syntax always felt more intuitive to me, and it being idempotent is part of that.

alias_neo 6y ago

Handling of directories and their contents (trailing slashes) is different.

stjohnswarts 6y ago
That tab completion will really get you sometimes :)

pletnes 6y ago

Scp works fine in gitbash, I’ve never found a windows-native rsync.

steerablesafe 6y ago
I never had a problem with cygwin rsync.
- jlokier 6y ago
  It sees the filesystem the way Cygwin maps it, so what's transferred isn't an exact match for Windows files and attributes. For example, Windows symlinks and Cygwin symlinks are quite different. I don't think Cygwin rsync can replicate a directory containing Windows symlinks properly, so that the replica behaves the same as seen by Windows programs. I'm not sure about the other Windows attributes such as ACLs but I would be surprised if Cygwin rsync can replicate those.
  - stjohnswarts 6y ago
    very few things can handle stuff like that going from windows->$another_os. You'll just have to compress them down with a format that understands those and preserves them and transfer it. Some of them don't even make sense on other filesystems.
    - jlokier 6y ago
      That's true. But sometimes you just want to move things from Windows to Windows. Then cygwin rsync isn't up to it. (scp isn't either.) That's different from MacOS, where there's a Mac-native version of rsync to transfer attributes that don't exist on $another_os.

40four 6y ago

Yeah I don’t quite understand that stance either. It seems like a great replacement. Rsync > scp in my opinion. I have always reached for it first.

eznzt 6y ago

rsync has a very restrictive licence.

kzrdude 6y ago
As a user-facing program it literally doesn't matter, it's only a political issue. You install it and you use it. The problem is if you're scared of the presence of GPLv3 for no reason.
- eznzt 6y ago
  It means that for example Mac OS or Windows will not bundle it by default.
  - kzrdude 6y ago
    Because they are scared of the presence of GPLv3 for no reason. Still a good point. Mac OS also doesn't ship modern GCC or Bash, so they are pretty much at war with reality at this point - or rather - creating their own ecosystem.
    - em-bee 6y ago
      every other unix system besides linux used to be like that. for many sysadmins the first action on a new unix server or workstation was to install gnu tools. apple decided to include those tools by default possibly in order to attract users. then they decided to stop updating and now macos is no better than those other unix systems used to be. i used a mac for a few years and i don't miss the experience. gnu/linux just works
  - zeveb 6y ago
    I think that problem is with macOS & Windows, not with rsync. There is no real reason why either cannot bundle it; they just choose not to.
pabs3 6y ago
There is openrsync if you don't like the rsync license. https://www.openrsync.org/ https://www.openrsync.org/