{"id":8933,"date":"2021-08-03T05:58:38","date_gmt":"2021-08-03T05:58:38","guid":{"rendered":"https:\/\/linuxways.net\/?p=8933"},"modified":"2021-08-03T05:58:46","modified_gmt":"2021-08-03T05:58:46","slug":"source-command-in-linux","status":"publish","type":"post","link":"https:\/\/linuxways.net\/de\/centos\/source-command-in-linux\/","title":{"rendered":"Source Command in Linux"},"content":{"rendered":"

Introduction<\/h2>\n

Source is a command to read a file then execute its contents. It helps to load variables, functions, and configuration files into shell scripts.<\/p>\n

Source is a shell built-in command and some shells in Linux and UNIX. It passed as an argument in the current shell script.<\/p>\n

This article will show you how to use the source command in Linux as we go through below.<\/p>\n

The syntax of source command<\/h2>\n
$ source FILENAME [ARGUMENTS]<\/pre>\n
We can replace source command by the .(dot)<\/p>\n
$ . FILENAME [ARGUMENTS]<\/pre>\n
How to use source command<\/h2>\n
1. Refresh current shell environment<\/strong><\/p>\n
When using Linux, a user can define alias in the current shell environment. For example, to display hidden files, we use ls -la. But we can use faster way by alias:<\/p>\n
$ alias la=\u2018ls -la\u2019<\/pre>\n
Then we only type la to display hidden file:<\/p>\n
<\/p>\n
But this is only temporary, for permanent use, open the .bashrc<\/strong> file and type:<\/p>\n
alias la= \u2018ls -la\u2019<\/pre>\n
<\/p>\n
Refresh the current shell environment, type:<\/p>\n
$ source ~\/.bashrc<\/pre>\n
2. Execute shell script in the current shell environment<\/strong><\/p>\n
A shell script can\u2019t understand the variables you define in the current shell environment. So we must use the source command.<\/p>\n
For example, we will try to run apt command<\/p>\n
Firstly, let\u2019s create file update.sh<\/strong> and start with:<\/p>\n
#!bin\/bash<\/pre>\n
Secondly, type the following command:<\/p>\n
sudo apt update<\/pre>\n
<\/p>\n
Lastly, save and execute it by source command:<\/p>\n
$ source .\/update.sh<\/pre>\n
Output:<\/p>\n
<\/p>\n
3. Import a shell function<\/strong><\/p>\n
For example:<\/p>\n
Firstly, let\u2019s create file foo.sh<\/strong> and start with:<\/p>\n
#!bin\/bash<\/pre>\n
Secondly, define a custom shell script. Here I put a function named foo<\/strong>:<\/p>\n
foo () {\r\n\r\necho \u201cHello\u201d\r\n\r\n}<\/pre>\n
<\/p>\n
Let\u2019s save it.<\/p>\n
To import the foo<\/strong> function, run the following command:<\/p>\n
$ source foo.sh<\/pre>\n
To run the shell function, type:<\/p>\n
$ foo<\/pre>\n
Output:<\/p>\n
<\/p>\n
4. Read and execute commands<\/strong><\/p>\n
Let’s say you want to execute 2 commands ls and df -h, let\u2019s create a file *txt<\/strong> contains those 2 commands. Here I will create file example.txt<\/strong>:<\/p>\n
<\/p>\n
And save it. Then run source filename:<\/p>\n
$ source example.txt<\/pre>\n
Output:<\/p>\n
<\/p>\n
Conclusion<\/h2>\n
You\u2019ve already gone through the details of how to use the source command in Linux.<\/p>\n
Thanks for reading.<\/p>","protected":false},"excerpt":{"rendered":"
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