**msynk** uses *rsync* to synchronise files or directories locally or between devices.
In general, you should always add a trailing '/' to directories.
## Encryption
Files can also be encrypted or decrypted using *mkrypt*. If encryption is used, the files are encrypted to a temporary directory and then synced with *rsync*.
If you sync encrypted files to your system, the encrypted files are transferred with *rsync* to a temporary directory and then decrypted to your filesystem.
## Configuration Files
**msynk** can read from config files usually stored in ~/.config/msynk.
To sync the directories "/home/user/foo" "/home/user/bar" and the file "/home/user/file.txt" to a remote server "user@foobar.com:~/backup" which is available with ssh at port 42, you could have a configuration file "my_backup":
```bash
sender=/home/user/
receiver=user@foobar.com:~/backup/
paths=(foo/ bar/ file.txt)
rsync_flags+=(--rsh="ssh -p 42")
```
You can then run this with: `msynk -c my_backup`, or if you only want to sync the "foo" directory and ".txt" files: `msynk -c my_backup foo .txt`
-`-c, --config config-name` Retrieve settings from config file ~/.config/msynk/*config-name*
-`--show-config config-name` Print variables defined from a config with *config-name*.
-`-s, --sender path` Set sender to directory. This can also be a remote, like user@domain.com:/dir. Defaults to to the current working directory.
-`-r, --receiver path` Set the receiver directory. All files and directories will be placed inside this directory. This can also be a remote, like user@domain.com:/dir. This option always needs to be set. Note that this directory must already exist if it is on a remote.
-`--reverse` Swaps sender and receiver. Useful when you want to reverse a config file.
-`--encrypt` Encrypt files with *mkrypt* before sending them to the receiver. The files are encrypted to $TMP_DIR and then synced to the receiver. Does not work with --delete.
-`--decrypt` Decrypt files with *mkrypt* after receiving them from the sender. Assumes that all files are encrypted and fails if that is not the case. The files are synced to $TMP_DIR and then decrypted to the receiver directory. Does not work with --delete.
-`--check-date` Can be used with -c and --encrypt or --decrypt: When running msynk with a config, the current date is stored in the config file. When running with --check-date, only files that have been modified after the date stored in the config file are processed (by passing--date [date the config was last run] to *mkrypt*).
-`--mkrypt-flag arg` Additional argument for *mkrypt*, for example to set the key for the encryption. Only pass one argument at a time, so for passing two use `--mkrypt-flag "arg1" --mkrypt-flag "arg2"`
-`-d, --delete`*rsync* --delete option. Deletes all files on the receiver that do not exist on the sender. *msynk* will open *less* with a list of all files that will be deleted and prompt you wether you want continue (unless --skip-dryrun is set)
-`--skip-dryrun` Can be used with --delete. This skips listing the files that will be deleted and the prompt.
-`--rsync-flag arg` Additional argument for *rsync*, for example to set the port for the connection. Only pass one argument at a time, so for passing two use `--rsync-flag "arg1" --rsync-flag "arg2"`
-`-v, --verbose` Increase verbosity: Passes -v to rsync and mkrypt.
-`--silent` Decrease verbosity: Print only error messages and passes --silent to mkrypt.
-`--debug` Maximum verbosity: -v but also print out rsync and mkrypt commands.
-`positional arguments` If you are using a config file: pos. args. are strings that have to be contained in a path in order for it to be synced. If no pos. args. are given, all files are synced. If you are not using a config file: pos. args. are filepaths relative to the sender directory.
When using --encrypt, the data is encrypted to a temporary directory $TMP_DIR, when using --decrypt the encrypted date is copied to the $TMP_DIR and then decrypted.
The $TMP_DIR defaults to /tmp/mksynk and /tmp is usually limited to half the size of your memory.
You change the $TMP_DIR in the script in /usr/bin/msynk or temporarily increase the size of the tmpfs by running `sudo mount -o remount,size=XXG,noatime /tmp` if your $TMP_DIR is on /tmp and you have at least XXGB memory+swap space.
