# __PUBLISH__ # bash-preexec.sh -- Bash support for ZSH-like 'preexec' and 'precmd' functions. # https://github.com/rcaloras/bash-preexec # # # 'preexec' functions are executed before each interactive command is # executed, with the interactive command as its argument. The 'precmd' # function is executed before each prompt is displayed. # # Author: Ryan Caloras (ryan@bashhub.com) # Forked from Original Author: Glyph Lefkowitz # # V0.3.7 # # General Usage: # # 1. Source this file at the end of your bash profile so as not to interfere # with anything else that's using PROMPT_COMMAND. # # 2. Add any precmd or preexec functions by appending them to their arrays: # e.g. # precmd_functions+=(my_precmd_function) # precmd_functions+=(some_other_precmd_function) # # preexec_functions+=(my_preexec_function) # # 3. Consider changing anything using the DEBUG trap or PROMPT_COMMAND # to use preexec and precmd instead. Preexisting usages will be # preserved, but doing so manually may be less surprising. # # Note: This module requires two Bash features which you must not otherwise be # using: the "DEBUG" trap, and the "PROMPT_COMMAND" variable. If you override # either of these after bash-preexec has been installed it will most likely break. # Avoid duplicate inclusion if [[ "${__bp_imported:-}" == "defined" ]]; then return 0 fi __bp_imported="defined" # Should be available to each precmd and preexec # functions, should they want it. $? and $_ are available as $? and $_, but # $PIPESTATUS is available only in a copy, $BP_PIPESTATUS. # TODO: Figure out how to restore PIPESTATUS before each precmd or preexec # function. __bp_last_ret_value="$?" BP_PIPESTATUS=("${PIPESTATUS[@]}") __bp_last_argument_prev_command="$_" __bp_inside_precmd=0 __bp_inside_preexec=0 # Fails if any of the given variables are readonly # Reference https://stackoverflow.com/a/4441178 __bp_require_not_readonly() { for var; do if ! ( unset "$var" 2> /dev/null ); then echo "bash-preexec requires write access to ${var}" >&2 return 1 fi done } # Remove ignorespace and or replace ignoreboth from HISTCONTROL # so we can accurately invoke preexec with a command from our # history even if it starts with a space. __bp_adjust_histcontrol() { local histcontrol histcontrol="${HISTCONTROL//ignorespace}" # Replace ignoreboth with ignoredups if [[ "$histcontrol" == *"ignoreboth"* ]]; then histcontrol="ignoredups:${histcontrol//ignoreboth}" fi; export HISTCONTROL="$histcontrol" } # This variable describes whether we are currently in "interactive mode"; # i.e. whether this shell has just executed a prompt and is waiting for user # input. It documents whether the current command invoked by the trace hook is # run interactively by the user; it's set immediately after the prompt hook, # and unset as soon as the trace hook is run. __bp_preexec_interactive_mode="" __bp_trim_whitespace() { local var=$@ var="${var#"${var%%[![:space:]]*}"}" # remove leading whitespace characters var="${var%"${var##*[![:space:]]}"}" # remove trailing whitespace characters echo -n "$var" } # This function is installed as part of the PROMPT_COMMAND; # It sets a variable to indicate that the prompt was just displayed, # to allow the DEBUG trap to know that the next command is likely interactive. __bp_interactive_mode() { __bp_preexec_interactive_mode="on"; } # This function is installed as part of the PROMPT_COMMAND. # It will invoke any functions defined in the precmd_functions array. __bp_precmd_invoke_cmd() { # Save the returned value from our last command, and from each process in # its pipeline. Note: this MUST be the first thing done in this function. __bp_last_ret_value="$?" BP_PIPESTATUS=("${PIPESTATUS[@]}") # Don't invoke precmds if we are inside an execution of an "original # prompt command" by another precmd execution loop. This avoids infinite # recursion. if (( __bp_inside_precmd > 0 )); then return fi local __bp_inside_precmd=1 # Invoke every function defined in our function array. local precmd_function for precmd_function in "${precmd_functions[@]}"; do # Only execute this function if it actually exists. # Test existence of functions with: declare -[Ff] if type -t "$precmd_function" 1>/dev/null; then __bp_set_ret_value "$__bp_last_ret_value" "$__bp_last_argument_prev_command" # Quote our function invocation to prevent issues with IFS "$precmd_function" fi done } # Sets a return value in $?. We may want to get access to the $? variable in our # precmd functions. This is available for instance in zsh. We can simulate it in bash # by setting the value here. __bp_set_ret_value() { return ${1:-} } __bp_in_prompt_command() { local prompt_command_array IFS=';' read -ra prompt_command_array <<< "$PROMPT_COMMAND" local trimmed_arg trimmed_arg=$(__bp_trim_whitespace "${1:-}") local command for command in "${prompt_command_array[@]:-}"; do local trimmed_command trimmed_command=$(__bp_trim_whitespace "$command") # Only execute each function if it actually exists. if [[ "$trimmed_command" == "$trimmed_arg" ]]; then return 0 fi done return 1 } # This function is installed as the DEBUG trap. It is invoked before each # interactive prompt display. Its purpose is to inspect the current # environment to attempt to detect if the current command is being invoked # interactively, and invoke 'preexec' if so. __bp_preexec_invoke_exec() { # Save the contents of $_ so that it can be restored later on. # https://stackoverflow.com/questions/40944532/bash-preserve-in-a-debug-trap#40944702 __bp_last_argument_prev_command="${1:-}" # Don't invoke preexecs if we are inside of another preexec. if (( __bp_inside_preexec > 0 )); then return fi local __bp_inside_preexec=1 # Checks if the file descriptor is not standard out (i.e. '1') # __bp_delay_install checks if we're in test. Needed for bats to run. # Prevents preexec from being invoked for functions in PS1 if [[ ! -t 1 && -z "${__bp_delay_install:-}" ]]; then return fi if [[ -n "${COMP_LINE:-}" ]]; then # We're in the middle of a completer. This obviously can't be # an interactively issued command. return fi if [[ -z "${__bp_preexec_interactive_mode:-}" ]]; then # We're doing something related to displaying the prompt. Let the # prompt set the title instead of me. return else # If we're in a subshell, then the prompt won't be re-displayed to put # us back into interactive mode, so let's not set the variable back. # In other words, if you have a subshell like # (sleep 1; sleep 2) # You want to see the 'sleep 2' as a set_command_title as well. if [[ 0 -eq "${BASH_SUBSHELL:-}" ]]; then __bp_preexec_interactive_mode="" fi fi if __bp_in_prompt_command "${BASH_COMMAND:-}"; then # If we're executing something inside our prompt_command then we don't # want to call preexec. Bash prior to 3.1 can't detect this at all :/ __bp_preexec_interactive_mode="" return fi local this_command this_command=$( export LC_ALL=C HISTTIMEFORMAT= builtin history 1 | sed '1 s/^ *[0-9][0-9]*[* ] //' ) # Sanity check to make sure we have something to invoke our function with. if [[ -z "$this_command" ]]; then return fi # If none of the previous checks have returned out of this function, then # the command is in fact interactive and we should invoke the user's # preexec functions. # Invoke every function defined in our function array. local preexec_function local preexec_function_ret_value local preexec_ret_value=0 for preexec_function in "${preexec_functions[@]:-}"; do # Only execute each function if it actually exists. # Test existence of function with: declare -[fF] if type -t "$preexec_function" 1>/dev/null; then __bp_set_ret_value ${__bp_last_ret_value:-} # Quote our function invocation to prevent issues with IFS "$preexec_function" "$this_command" preexec_function_ret_value="$?" if [[ "$preexec_function_ret_value" != 0 ]]; then preexec_ret_value="$preexec_function_ret_value" fi fi done # Restore the last argument of the last executed command, and set the return # value of the DEBUG trap to be the return code of the last preexec function # to return an error. # If `extdebug` is enabled a non-zero return value from any preexec function # will cause the user's command not to execute. # Run `shopt -s extdebug` to enable __bp_set_ret_value "$preexec_ret_value" "$__bp_last_argument_prev_command" } __bp_install() { # Exit if we already have this installed. if [[ "${PROMPT_COMMAND:-}" == *"__bp_precmd_invoke_cmd"* ]]; then return 1; fi trap '__bp_preexec_invoke_exec "$_"' DEBUG # Preserve any prior DEBUG trap as a preexec function local prior_trap=$(sed "s/[^']*'\(.*\)'[^']*/\1/" <<<"${__bp_trap_string:-}") unset __bp_trap_string if [[ -n "$prior_trap" ]]; then eval '__bp_original_debug_trap() { '"$prior_trap"' }' preexec_functions+=(__bp_original_debug_trap) fi # Adjust our HISTCONTROL Variable if needed. __bp_adjust_histcontrol # Issue #25. Setting debug trap for subshells causes sessions to exit for # backgrounded subshell commands (e.g. (pwd)& ). Believe this is a bug in Bash. # # Disabling this by default. It can be enabled by setting this variable. if [[ -n "${__bp_enable_subshells:-}" ]]; then # Set so debug trap will work be invoked in subshells. set -o functrace > /dev/null 2>&1 shopt -s extdebug > /dev/null 2>&1 fi; # Install our hooks in PROMPT_COMMAND to allow our trap to know when we've # actually entered something. PROMPT_COMMAND="__bp_precmd_invoke_cmd; __bp_interactive_mode" # Add two functions to our arrays for convenience # of definition. precmd_functions+=(precmd) preexec_functions+=(preexec) # Since this function is invoked via PROMPT_COMMAND, re-execute PC now that it's properly set eval "$PROMPT_COMMAND" } # Sets our trap and __bp_install as part of our PROMPT_COMMAND to install # after our session has started. This allows bash-preexec to be included # at any point in our bash profile. Ideally we could set our trap inside # __bp_install, but if a trap already exists it'll only set locally to # the function. __bp_install_after_session_init() { # Make sure this is bash that's running this and return otherwise. if [[ -z "${BASH_VERSION:-}" ]]; then return 1; fi # bash-preexec needs to modify these variables in order to work correctly # if it can't, just stop the installation __bp_require_not_readonly PROMPT_COMMAND HISTCONTROL HISTTIMEFORMAT || return # If there's an existing PROMPT_COMMAND capture it and convert it into a function # So it is preserved and invoked during precmd. if [[ -n "$PROMPT_COMMAND" ]]; then eval '__bp_original_prompt_command() { '"$PROMPT_COMMAND"' }' precmd_functions+=(__bp_original_prompt_command) fi # Installation is finalized in PROMPT_COMMAND, which allows us to override the DEBUG # trap. __bp_install sets PROMPT_COMMAND to its final value, so these are only # invoked once. # It's necessary to clear any existing DEBUG trap in order to set it from the install function. # Using \n as it's the most universal delimiter of bash commands PROMPT_COMMAND=$'\n__bp_trap_string="$(trap -p DEBUG)"\ntrap DEBUG\n__bp_install\n' } # Run our install so long as we're not delaying it. if [[ -z "$__bp_delay_install" ]]; then __bp_install_after_session_init fi;