Question

Is there a way to include another shell script in a shell script to be able to access its functions?

Like how in PHP you can use the include directive with other PHP files in order to run the functions that are contained within simply by calling the function name.

Answer 1

Simply put inside your script :

source FILE

Or

. FILE # POSIX compliant

$ LANG=C help source
source: source filename [arguments]
Execute commands from a file in the current shell.

Read and execute commands from FILENAME in the current shell.  The
entries in $PATH are used to find the directory containing FILENAME.
If any ARGUMENTS are supplied, they become the positional parameters
when FILENAME is executed.

Exit Status:
Returns the status of the last command executed in FILENAME; fails if
FILENAME cannot be read.