bash¶

Strictly speaking, this is not all bash. It's command line unix.

Bash string manipulation using parameter expansion

Cool tricks¶

variable+x

Commands¶

Command	Description
`bash --norc`	Starts Bash shell without reading startup files (~/.bashrc, ~/.profile)

Keyboard shortcuts¶

shortcut	action
Ctrl+k	delete to end of line
Ctrl+u	delete to start of line

Scripting¶

Mapfile: Read lines from the standard input into an indexed array variable.

"Busybox" style function execution via "symlinked binaries"¶

Make certain functions from a file executable:

bin/git-artifact-repo-update -> ../lib/functions

https://en.wikipedia.org/wiki/BusyBox

# Execute function with same name as file called unless sourced
if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
  "$(basename "$0")" "$@"
fi

SCRIPT_DIR: directory holding script¶

Follow symlinks: Ensures scripts symlinked into ~/.local/bin can find ../lib:

command -v realpath &> /dev/null || {
  echo "Error: 'realpath' is required but not found. Please install 'coreutils' (e.g. 'brew install coreutils' on macOS)." >&2
  exit 1
}
SCRIPT_DIR="$(dirname -- "$(realpath "${BASH_SOURCE[0]}")")"

Request user confirmation¶

local regex_yes="^[Yy]$"
read -p "Are you sure you want to continue? " -n 1 -r
echo
if [[ $REPLY =~ $regex_yes ]]

Default to Yes:

local regex_yes="^[Yy]?$"  # The '?' after [Yy] allows for an empty response to be treated as 'Yes'
read -p "Are you sure you want to continue? (Y/n) " -n 1 -r
echo  # Move to a new line
if [[ ! $REPLY =~ $regex_yes ]]; then
    echo "Update cancelled."
    return 1  # Exit the function with a non-zero exit status to indicate failure
else
    echo "Proceeding with update."
fi