Difference between a semicolon and a new line in bash ("source rcfile; foo" vs. "source rcfile<NEWLINE>foo" where "foo" is an alias defined in rcfile)

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I thought that giving a semicolon in bash is the same as giving a new line, just combining multiple lines.

However, with alias sudo='sudo -i' in the .bashrc file, the below result doesn't seem to work as I expected:

USER@HOST:~:$ cat tmp-1.sh
#!/bin/bash
source ~/.bashrc; sudo env | grep PATH

USER@HOST:~:$ cat tmp-2.sh
#!/bin/bash
source ~/.bashrc
sudo env | grep PATH

USER@HOST:~:$ ./tmp-1.sh
PATH=/usr/bin:/bin:/usr/sbin:/sbin

USER@HOST:~:$ ./tmp-2.sh
PATH=/home1/client/bin:/usr/python-3.8.2-r2/bin:/usr/jdk64/jdk1.8.0_112/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/bin:/root/bin

What's the difference between these two?

bash
1 Answers

As in your comment:

alias sudo='sudo -i' is in .bashrc file

According to man bash:

The rules concerning the definition and use of aliases are somewhat confusing. Bash always reads at least one complete line of input, and all lines that make up a compound command, before executing any of the commands on that line or the compound command. Aliases are expanded when a command is read, not when it is executed. Therefore, an alias definition appearing on the same line as another command does not take effect until the next line of input is read. The commands following the alias definition on that line are not affected by the new alias. This behavior is also an issue when functions are executed. Aliases are expanded when a function definition is read, not when the function is executed, because a function definition is itself a command. As a consequence, aliases defined in a function are not available until after that function is executed. To be safe, always put alias definitions on a separate line, and do not use alias in compound commands.

For almost every purpose, aliases are superseded by shell functions.

user_9000780
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