test -L

The following code will populate the variables SCRIPT_NAME and SCRIPT_DIR with the name of the script currently being execute and the location this script is in:

SCRIPT_NAME=$(basename $(test -L "$0" && readlink "$0" || echo "$0"));
SCRIPT_DIR=$(cd $(dirname "$0") && pwd);

Notes for SCRIPT_NAME:

• $0 expands to the name of the shell or shell script
• test -L "$0" checks that input is a file that exists and is a symbolic link
• && readlink "$0" will be executed if the above statement is true and it will print the resolved symbolic link
• || echo "$0" will be executed if the test for symbolic link fails
• finally, basename will strip directory and suffix from whatever is returned from the above statements

Notes for SCRIPT_DIR:

• Will not resolve the correct folder if the last component of the path is a symbolic link (symlink). It will return the location of the symlink instead of the location of the file the symlink is pointing to
• cd will return 0 if it successfully navigates to a directory or 1 when it fails to navigate to the directory
• cd "$( dirname "$0" )" will use dirname to strip the last component from the expanded name and try to navigate to that location
• if the above cd fails, we get the current location using && pwd. pwd will print name of current/working directory

In case you have a problem with $0, it is overwritten or the above function is called by a child script in another folder you can replace $0 with ${BASH_SOURCE[0]}.

SCRIPT_NAME=$(basename $(test -L "${BASH_SOURCE[0]}" && readlink "${BASH_SOURCE[0]}" || echo "${BASH_SOURCE[0]}"));
SCRIPT_DIR=$(cd $(dirname "${BASH_SOURCE[0]}") && pwd);