Bash Utilities

bash-utils.sh

#
# You can import this script in your current bash using the following command
# source <(curl -s https://gist.githubusercontent.com/renelink/34066cb9204e5a072e7f4d284011f887/raw/bash-utils.sh)
#
# You can also put these lines in your .bashrc or .bash_profile to automatically install the utils if they do not exist
#
# -----------------------------
# BASH_UTILS_FILE="${HOME}/.bash-utils.sh"
#
# if ! [ -f "${BASH_UTILS_FILE}" ]; then
#   curl -o "$BASH_UTILS_FILE"  https://gist.githubusercontent.com/renelink/34066cb9204e5a072e7f4d284011f887/raw/bash-utils.sh
# fi
#
# . "$BASH_UTILS_FILE"
# -----------------------------
#
# To update the git-utils you can then just execute
# $ rm ~/.bash-utils.sh
# and reopen the shell


# This funciton reads an environment variable's content from stdin so that it will not occur in the shell's history.
# It is useful when you need to export a variable with sensitive content like a private gpg key or passphrase.
#
# Usage: exportSecret ENVIRONMENT_VARIABLE_NAME
#
# In some situations you have to press CTRL-D two times, e.g. when no new line is entered.
# See https://unix.stackexchange.com/questions/701317/when-using-cat-to-create-file-i-have-to-type-ctrld-twice-to-finish-the-input
#
function exportSecret(){
    local env_var_name="$1"

    if [ -z "${env_var_name}" ]; then
        >&2 echo "Pass the environment variable name as the first argument."
    return

    fi

    >&2 echo "Enter the secret value and finish with CTRL-D. Abort with CTRL-C."

    IFS='' read -s -r -d '' ${env_var_name} < <(cat)
    export ${env_var_name}
}


# Executes an isolated bash shell that does not load any rc or profile files and uses the PS1 provided by ISOLATED_PS1.
# The isolated bash will not record a history.
#
# This is useful if you want to do operations with sensitive data. Just exit the shell and even sensitive data that
# you put in environment variables is deleted. Such as gpg keys or passphrases.
#
alias bash-isolated='bash --rcfile <(echo "export PS1=\"$ISOLATED_PS1\";unset HISTFILE")'

# Change this line to the default isolated bash PS1
export ISOLATED_PS1='\[\e]0;\w\a\]\n\[\e[32m\]\u@\h \[\e[35m\]$MSYSTEM\[\e[0m\] \[\e[33m\]\w\[\e[0m\] \[\e[31m\](ISOLATED)\[\e[0m\]\n$ '


# Delte a history range.
histdel(){
  local start="$1"
  local end="$2"

  if [ -z "$start" ]; then echo "Usage: histdel START_INDEX [END_INDEX]"; return; fi

  if [ -z "$end" ]; then
     end=$(history 1 | awk '{print $1}')
  fi

  for h in $(seq $end -1 $start); do
    history -d $h
  done

  history -w # force write
}