#047
Comparing methods for synchronizing local folders - cp, rsync.
Notes
Problem: need to make or update a copy of a folder to another local folder. This may be for deployment purposes or just some disk management.
Recursive Copy
On *nix-type systems, the cp -R makes a recursive copy.
Advantages:
- simple
- built-in shell command (no dependencies)
Disadvantages:
- does not help making a true mirror (i.e. deletions do not propagate)
- inefficient - copies everything even if redundant
Example:
$ ./make_example_source.sh
Making a fresh copy of ./original
$ ./use_recursive_copy.sh
Making a copy of ./original in ./copy
Using rsync
Most *nix-type systems will have an rsync program available (or it can be installed).
Advantages:
- can do a proper mirror, including propagating deletions
- efficient - only copies differences
Disadvantages:
- may not be natively available
- a little more unusual - need to read the man page
Example:
$ ./make_example_source.sh
Making a fresh copy of ./original
$ ./use_rsync.sh
Performing pristine copy of ./original/ to ./copy
building file list ... done
created directory ./copy
./
1.txt
2.txt
sub1/
sub1/1.txt
sub1/2.txt
sub2/
sub2/1.txt
sub2/2.txt
sent 512 bytes received 170 bytes 1364.00 bytes/sec
total size is 32 speedup is 0.05
Adding 3.txt to source and removing 1.txt from dest
And update with sync..
building file list ... done
1.txt
3.txt
sent 305 bytes received 64 bytes 738.00 bytes/sec
total size is 34 speedup is 0.09