# Xtrabackup: Error: unknown argument: './'

**URL:** <https://forums.percona.com/t/xtrabackup-error-unknown-argument/7186>\
**Category:** Percona XtraBackup\
**Created:** [September 4, 2019, 10:01pm UTC](https://forums.percona.com/t/xtrabackup-error-unknown-argument/7186 "2019-09-04T22:01:39Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Fan](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/fan/32/40_2.png) [@Fan](https://forums.percona.com/u/Fan)\
**Post date:** [September 4, 2019, 10:01pm UTC](https://forums.percona.com/t/xtrabackup-error-unknown-argument/7186/1 "2019-09-04T22:01:39Z")

</div>

In the doc of \<\>  
On the destination host:  
`$ nc -l 9999 | cat - > /data/backups/backup.xbstream`  
On the source host:  
`$ xtrabackup --backup --stream=xbstream ./ | nc desthost 9999`

but

```
$xtrabackup --defaults-file=/data/mysql_3307/my_3307.cnf --backup --slave-info --binlog-info=ON --tmpdir=/rundata/tmp/ --host=127.0.0.1 --port=3307 -u'superuser' -p'supersecurt' --stream=xbstream ./| nc 192.168.4.224 64036 
xtrabackup: recognized server arguments: --server-id=0040363307 --datadir=/data/mysql_3307/data --open_files_limit=65535 --innodb_buffer_pool_size=10G --innodb_io_capacity=2000 --innodb_flush_method=O_DIRECT --innodb_undo_tablespaces=3 --innodb_log_file_size=1G --innodb_log_files_in_group=5 --innodb_log_buffer_size=32M --innodb_write_io_threads=8 --innodb_read_io_threads=8 --innodb_file_per_table=1 --innodb_open_files=65535 --innodb_data_file_path=ibdata1:1G:autoextend --innodb_flush_log_at_trx_commit=1 --innodb_checksums=1 --innodb_checksum_algorithm=crc32 --log_bin=/data/mysql_3307/logs/0040363307-mysql-bin --tmpdir=/rundata/tmp/ 
xtrabackup: recognized client arguments: --server-id=0040363307 --datadir=/data/mysql_3307/data --open_files_limit=65535 --innodb_buffer_pool_size=10G --innodb_io_capacity=2000 --innodb_flush_method=O_DIRECT --innodb_undo_tablespaces=3 --innodb_log_file_size=1G --innodb_log_files_in_group=5 --innodb_log_buffer_size=32M --innodb_write_io_threads=8 --innodb_read_io_threads=8 --innodb_file_per_table=1 --innodb_open_files=65535 --innodb_data_file_path=ibdata1:1G:autoextend --innodb_flush_log_at_trx_commit=1 --innodb_checksums=1 --innodb_checksum_algorithm=crc32 --log_bin=/data/mysql_3307/logs/0040363307-mysql-bin --tmpdir=/rundata/tmp/ --backup=1 --slave-info=1 --binlog-info=ON --host=127.0.0.1 --port=3307 --user=an_master --password=* --stream=xbstream 
xtrabackup: Error: unknown argument: './'

```

xtrabackup: Error: unknown argument: ‘./’

is this should be --target-dir=./ ? is this a doc error?

 ![photoid=54576](https://us1.discourse-cdn.com/flex019/uploads/percona1/original/2X/e/e6db2e1ad8c9e7df84feb6157fc238679f717cd2.jpeg)

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<div class="post-metadata">

**Author:** ![matthewb](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/matthewb/32/34_2.png) [@matthewb](https://forums.percona.com/u/matthewb)\
**Post date:** [January 4, 2021, 8:47pm UTC](https://forums.percona.com/t/xtrabackup-error-unknown-argument/7186/2 "2021-01-04T20:47:03Z")

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This seems to be a doc error. You should use `--target-dir /path/to/mysql` to be explicit and avoid any issues.