dump the current environment into .env file format (multiline values are quoted) while ignorning common variables.

envdump.sh

#!/usr/bin/env bash
# dumps the current environment into .env file format (multiline values are quoted) while ignorning common variables.
# additional ignore list can be provided as arguments.

# common variables to ignore
declare -a COMMON_IGNORE_LIST=(
    "_"
    "COLORTERM"
    "GEM_CACHE"
    "GEM_HOME"
    "GEM_PATH"
    "GEM_ROOT"
    "GEM_SPEC_CACHE"
    "HOME"
    "HOSTNAME"
    "JAVA_HOME"
    "JAVA_OPTS"
    "LANG"
    "LC_CTYPE"
    "LC_TYPE"
    "LOGNAME"
    "MAIL"
    "OLDPWD"
    "PATH"
    "PS1"
    "PWD"
    "RUBY_ROOT"  
    "SHELL"
    "SHLVL"
    "SSH_AGENT_PID"
    "SSH_AUTH_SOCK"
    "SSH_CONNECTION"
    "SSH_TTY"
    "TERM_PROGRAM_VERSION"
    "TERM_PROGRAM"
    "TERM_SESSION_ID"
    "TERM"
    "TMPDIR"
    "USER"
) 

# additional ignore list
declare -a ADDITIONAL_IGNORE_LIST=("$@")

# combine ignore lists
declare -a IGNORE_LIST=("${COMMON_IGNORE_LIST[@]}" "${ADDITIONAL_IGNORE_LIST[@]}")

# dump environment
for var in $(compgen -e); do
    if [[ ! " ${IGNORE_LIST[*]} " =~ " ${var} " ]]; then
        echo "${var}=\"${!var//\"/\\\"}\""
    fi
done