Two new lines of code added by nvm in .bashrc for explanation

after installing nvm, I found two lines of code in .bashrc: 

export NVM_DIR="/root/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"  -sharp This loads nvm

ask for advice, the second line of code . What does the preceding . in "$NVM_DIR/nvm.sh" mean?

Shell nvm
Mar.23,2021

. Equivalent to souce command

Previous: Does the checked setting for input not work?

Next: What is the value returned by clicking clickName in ECharts?

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b381f4-2c0f6.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b381f4-2c0f6.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?