Introspecting and manipulating the shell environment
Code Snippets
if [[ ${var+x} ]]; then # var is set but it could be empty
if [[ ! ${var+x} ]]; then # var is not set
if [[ ${var+x} && ! $var ]]; then # var is set and is empty
# Alternatively
if [[ -v var ]]; then # var is set but it could be empty
if [[ ! -v var ]]; then # var is not set
if [[ -v var && ! $var ]]; then # var is set and is empty
if [[ -v var && -z $var ]]; then # var is set and is empty
# works most reliably
SRC_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
[[ "${BASH_SOURCE[0]}" != "${0}" ]] && SOURCED=1
if [ -z "$SOURCED" ]; then
pretty_error "This script needs to be sourced, i.e. source './virtualenv.bash', not './virtualenv.bash'"
exit 1
fi