How can the last command's wall time be put in the Bash prompt?

Bash Problem Overview

Is there a way to embed the last command's elapsed wall time in a Bash prompt? I'm hoping for something that would look like this:

[last: 0s][/my/dir]$ sleep 10
[last: 10s][/my/dir]$

Background

I often run long data-crunching jobs and it's useful to know how long they've taken so I can estimate how long it will take for future jobs. For very regular tasks, I go ahead and record this information rigorously using appropriate logging techniques. For less-formal tasks, I'll just prepend the command with time.

It would be nice to automatically time every single interactive command and have the timing information printed in a few characters rather than 3 lines.

Bash Solutions

Solution 1 - Bash

This is minimal stand-alone code to achieve what you want:

function timer_start {
  timer=${timer:-$SECONDS}
}

function timer_stop {
  timer_show=$(($SECONDS - $timer))
  unset timer
}

trap 'timer_start' DEBUG
PROMPT_COMMAND=timer_stop

PS1='[last: ${timer_show}s][\w]$ '

Solution 2 - Bash

Using your replies and some other threads, I wrote this prompt which I want to share with you. I took a screenshot in wich you can see :

White : Last return code
Green and tick mark means success (return code was 0)
Red and cross mark means error (return code was >0)
(Green or Red) : Last command execution time in parenthesis
(Green or Red) : Current date time (\t)
(Green if not root, Red if root) : the logged username
(Green) : the server name
(Blue) : the pwd directory and the usual $

Here is the code to put in your ~/.bashrc file :

function timer_now {
	date +%s%N
}

function timer_start {
	timer_start=${timer_start:-$(timer_now)}
}

function timer_stop {
	local delta_us=$((($(timer_now) - $timer_start) / 1000))
	local us=$((delta_us % 1000))
	local ms=$(((delta_us / 1000) % 1000))
	local s=$(((delta_us / 1000000) % 60))
	local m=$(((delta_us / 60000000) % 60))
	local h=$((delta_us / 3600000000))
	# Goal: always show around 3 digits of accuracy
	if ((h > 0)); then timer_show=${h}h${m}m
	elif ((m > 0)); then timer_show=${m}m${s}s
	elif ((s >= 10)); then timer_show=${s}.$((ms / 100))s
	elif ((s > 0)); then timer_show=${s}.$(printf %03d $ms)s
	elif ((ms >= 100)); then timer_show=${ms}ms
	elif ((ms > 0)); then timer_show=${ms}.$((us / 100))ms
	else timer_show=${us}us
	fi
	unset timer_start
}


set_prompt () {
	Last_Command=$? # Must come first!
	Blue='\[\e[01;34m\]'
	White='\[\e[01;37m\]'
	Red='\[\e[01;31m\]'
	Green='\[\e[01;32m\]'
	Reset='\[\e[00m\]'
	FancyX='\342\234\227'
	Checkmark='\342\234\223'


	# Add a bright white exit status for the last command
	PS1="$White\$? "
	# If it was successful, print a green check mark. Otherwise, print
	# a red X.
	if [[ $Last_Command == 0 ]]; then
		PS1+="$Green$Checkmark "
	else
		PS1+="$Red$FancyX "
	fi

	# Add the ellapsed time and current date
	timer_stop
	PS1+="($timer_show) \t "

	# If root, just print the host in red. Otherwise, print the current user
	# and host in green.
	if [[ $EUID == 0 ]]; then
		PS1+="$Red\\u$Green@\\h "
	else
		PS1+="$Green\\u@\\h "
	fi
	# Print the working directory and prompt marker in blue, and reset
	# the text color to the default.
	PS1+="$Blue\\w \\\$$Reset "
}

trap 'timer_start' DEBUG
PROMPT_COMMAND='set_prompt'

Solution 3 - Bash

Another very minimal approach is:

trap 'SECONDS=0' DEBUG
export PS1='your_normal_prompt_here ($SECONDS) # '

This shows the number of seconds since the last simple command was started. The counter is not reset if you simply hit Enter without entering a command -- which can be handy when you just want to see how long the terminal has been up since you last did anything in it. It works fine for me in Red Hat and Ubuntu. It did NOT work for me under Cygwin, but I'm not sure if that's a bug or just a limitation of trying to run Bash under Windows.

One possible drawback to this approach is that you keep resetting SECONDS, but if you truly need to preserve SECONDS as the number of seconds since initial shell invocation, you can create your own variable for the PS1 counter instead of using SECONDS directly. Another possible drawback is that a large seconds value such as "999999" might be be better displayed as days+hours+minutes+seconds, but it's easy to add a simple filter such as:

seconds2days() { # convert integer seconds to Ddays,HH:MM:SS
  printf "%ddays,%02d:%02d:%02d" $(((($1/60)/60)/24)) \
  $(((($1/60)/60)%24)) $((($1/60)%60)) $(($1%60)) |
  sed 's/^1days/1day/;s/^0days,\(00:\)*//;s/^0//' ; }
trap 'SECONDS=0' DEBUG
PS1='other_prompt_stuff_here ($(seconds2days $SECONDS)) # '

This translates "999999" into "11days,13:46:39". The sed at the end changes "1days" to "1day", and trims off empty leading values such as "0days,00:". Adjust to taste.

Solution 4 - Bash

You could utilize this zsh-borrowed hook for bash: http://www.twistedmatrix.com/users/glyph/preexec.bash.txt

Timing done with this hook (Mac OS X): Use Growl to monitor long-running shell commands

Solution 5 - Bash

If you hadn't set up any of the other answers before you kicked off your long-running job and you just want to know how long the job took, you can do the simple

$ HISTTIMEFORMAT="%s " history 2

and it will reply with something like

  654  1278611022 gvn up
  655  1278611714 HISTTIMEFORMAT="%s " history 2

and you can then just visually subtract the two timestamps (anybody know how to capture the output of the shell builtin history command?)

Solution 6 - Bash

I took the answer from Ville Laurikari and improved it using the time command to show sub-second accuracy:

function timer_now {
  date +%s%N
}

function timer_start {
  timer_start=${timer_start:-$(timer_now)}
}

function timer_stop {
  local delta_us=$((($(timer_now) - $timer_start) / 1000))
  local us=$((delta_us % 1000))
  local ms=$(((delta_us / 1000) % 1000))
  local s=$(((delta_us / 1000000) % 60))
  local m=$(((delta_us / 60000000) % 60))
  local h=$((delta_us / 3600000000))
  # Goal: always show around 3 digits of accuracy
  if ((h > 0)); then timer_show=${h}h${m}m
  elif ((m > 0)); then timer_show=${m}m${s}s
  elif ((s >= 10)); then timer_show=${s}.$((ms / 100))s
  elif ((s > 0)); then timer_show=${s}.$(printf %03d $ms)s
  elif ((ms >= 100)); then timer_show=${ms}ms
  elif ((ms > 0)); then timer_show=${ms}.$((us / 100))ms
  else timer_show=${us}us
  fi
  unset timer_start
}

trap 'timer_start' DEBUG
PROMPT_COMMAND=timer_stop

PS1='[last: ${timer_show}][\w]$ '

Of course this requires a process to be started, so it's less efficient, but still fast enough that you wouldn't notice.

Solution 7 - Bash

I found that trap ... DEBUG was running every time $PROMPT_COMMAND was called, resetting the timer, and therefore always returning 0.

However, I found that history records times, and I tapped into these to get my answer:

HISTTIMEFORMAT='%s '
PROMPT_COMMAND="
  START=\$(history 1 | cut -f5 -d' ');
  NOW=\$(date +%s);
  ELAPSED=\$[NOW-START];
  $PROMPT_COMMAND"
PS1="\$ELAPSED $PS1"

It's not perfect though:

If history doesn't register the command (e.g. repeated or ignored commands), the start time will be wrong.
Multi-line commands don't get the date extracted properly from history.

Solution 8 - Bash

Here's my take on Thomas'

uses date +%s%3N to get milliseconds as base unit, simplified following code (less zeros)

function t_now {
    date +%s%3N
}

function t_start {
    t_start=${t_start:-$(t_now)}
}

function t_stop {
    local d_ms=$(($(t_now) - $t_start))
    local d_s=$((d_ms / 1000))
    local ms=$((d_ms % 1000))
    local s=$((d_s % 60))
    local m=$(((d_s / 60) % 60))
    local h=$((d_s / 3600))
    if ((h > 0)); then t_show=${h}h${m}m
    elif ((m > 0)); then t_show=${m}m${s}s
    elif ((s >= 10)); then t_show=${s}.$((ms / 100))s
    elif ((s > 0)); then t_show=${s}.$((ms / 10))s
    else t_show=${ms}ms
    fi
    unset t_start
}
set_prompt () {
t_stop
}

trap 't_start' DEBUG
PROMPT_COMMAND='set_prompt'

Then add $t_show to your PS1

Solution 9 - Bash

Another approach for bash 4.x and above would be to use coproc with PS0 and PS1 like below:

cmd_timer()
{
    echo $(( SECONDS - $(head -n1 <&"${CMD_TIMER[0]}") ))
}

coproc CMD_TIMER ( while read; do echo $SECONDS; done )
echo '' >&"${CMD_TIMER[1]}" # For value to be ready on first PS1 expansion
export PS0="\$(echo '' >&${CMD_TIMER[1]})"
export PS1="[ \$(cmd_timer) ] \$"

This is a .bashrc ready snippet. It is especially useful for everyone that uses undistract-me which overwrites trap DEBUG for its own purposes.

Solution 10 - Bash

If somone just wants to see the time of execution, add this line to bash_profile

trap 'printf "t=%s\n" $(date +%T.%3N)' DEBUG

Solution 11 - Bash

Translated version for zsh.

Append to your ~/.zshrc file

function preexec() {
  timer=$(date +%s%3N)
}

function precmd() {
  if [ $timer ]; then
    local now=$(date +%s%3N)
    local d_ms=$(($now-$timer))
    local d_s=$((d_ms / 1000))
    local ms=$((d_ms % 1000))
    local s=$((d_s % 60))
    local m=$(((d_s / 60) % 60))
    local h=$((d_s / 3600))
    if ((h > 0)); then elapsed=${h}h${m}m
    elif ((m > 0)); then elapsed=${m}m${s}s
    elif ((s >= 10)); then elapsed=${s}.$((ms / 100))s
    elif ((s > 0)); then elapsed=${s}.$((ms / 10))s
    else elapsed=${ms}ms
    fi

    export RPROMPT="%F{cyan}${elapsed} %{$reset_color%}"
    unset timer
  fi
}

Solution 12 - Bash

Will putting a \t in PS1 work for you?

It does not give the elapsed time but it should be easy enough to subtract the times when necessary.

$ export PS1='[\t] [\w]\$ '
[14:22:30] [/bin]$ sleep 10
[14:22:42] [/bin]$

Following the OP's comment that he is already using \t. If you can use tcsh instead of bash, you can set the time variable.

/bin 1 > set time = 0
/bin 2 > sleep 10
0.015u 0.046s 0:10.09 0.4%      0+0k 0+0io 2570pf+0w
/bin 3 >

You can change the format of the printing to be less ugly (se the tcsh man page).

/bin 4 > set time = ( 0 "last: %E" )
/bin 5 > sleep 10
last: 0:10.09
/bin 6 >

I do not know of a similar facility in bash

Solution 13 - Bash

this is my version

use date to format time, only calc days
set terminal title
use $ in PS1 for user $ + root #
show return code / exit code
use date -u to disable DST
use hidden names like _foo

_x_dt_min=1 # minimum running time to show delta T
function _x_before {
    _x_t1=${_x_t1:-$(date -u '+%s.%N')} # float seconds
}
function _x_after {
    _x_rc=$? # return code
    _x_dt=$(echo $(date -u '+%s.%N') $_x_t1 | awk '{printf "%f", $1 - $2}')
    unset _x_t1
    #_x_dt=$(echo $_x_dt | awk '{printf "%f", $1 + 86400 * 1001}') # test
    # only show dT for long-running commands
    # ${f%.*} = int(floor(f))
    (( ${_x_dt%.*} >= $_x_dt_min )) && {
        _x_dt_d=$((${_x_dt%.*} / 86400))
        _x_dt_s='' # init delta T string
        (( $_x_dt_d > 0 )) && \
            _x_dt_s="${_x_dt_s}${_x_dt_d} days + "
        # format time
        # %4N = four digits of nsec
        _x_dt_s="${_x_dt_s}$(date -u -d0+${_x_dt}sec '+%T.%4N')"
        PS1='rc = ${_x_rc}\ndT = ${_x_dt_s}\n\$ '
    } || {
        PS1='rc = ${_x_rc}\n\$ '
    }
    # set terminal title to terminal number
    printf "\033]0;%s\007" $(tty | sed 's|^/dev/\(pts/\)\?||')
}
trap '_x_before' DEBUG
PROMPT_COMMAND='_x_after'
PS1='\$ '

sample output:

$ sleep 0.5
rc = 0
$ sleep 1
rc = 0
dT = 00:00:01.0040
$ sleep 1001d
rc = 0
dT = 1001 days + 00:00:00.0713
$ false
rc = 1
$

Solution 14 - Bash

A version with split hours, minutes and seconds inspired by the zsh spaceship prompt, based on Ville's answer and this time conversion function by perreal.

I also added a threshold variable so that the timer only displays for long running commands.

time_threshold=5;

function convert_secs {
	((h=${1}/3600))
	((m=(${1}%3600)/60))
	((s=${1}%60))
	if [ $h -gt 0 ]; then printf "${h}h "; fi
	if [ $h -gt 0 ] || [ $m -gt 0 ]; then printf "${m}m "; fi
	if [ $s -gt 0 ]; then printf "${s}s "; fi
}

function timer_start {
	timer=${timer:-$SECONDS}
}

function timer_stop {
	timer_time=$(($SECONDS - $timer))
	
	if [ ! -z $timer_time ] && [ $timer_time -ge ${time_threshold} ]; then
		timer_show="took $(convert_secs $timer_time)"
	else
		timer_show=""
	fi

	unset timer
}

trap 'timer_start' DEBUG
PROMPT_COMMAND=timer_stop

PS1='\n\w ${timer_show}\n\\$ '

For the coloured output in my screenshot:

bold=$(tput bold)
reset=$(tput sgr0)
yellow=$(tput setaf 3)
cyan=$(tput setaf 6)

PS1='\n${bold}${cyan}\w ${yellow}${timer_show}${reset}\n\\$ '

Content Type	Original Author	Original Content on Stackoverflow
Question	Mr Fooz	View Question on Stackoverflow
Solution 1 - Bash	Ville Laurikari	View Answer on Stackoverflow
Solution 2 - Bash	Nicolas Thery	View Answer on Stackoverflow
Solution 3 - Bash	willdye	View Answer on Stackoverflow
Solution 4 - Bash	miku	View Answer on Stackoverflow
Solution 5 - Bash	philsnow	View Answer on Stackoverflow
Solution 6 - Bash	Thomas	View Answer on Stackoverflow
Solution 7 - Bash	PJSCopeland	View Answer on Stackoverflow
Solution 8 - Bash	Ju Tutt	View Answer on Stackoverflow
Solution 9 - Bash	kamren	View Answer on Stackoverflow
Solution 10 - Bash	Mendi Barel	View Answer on Stackoverflow
Solution 11 - Bash	Ju Tutt	View Answer on Stackoverflow
Solution 12 - Bash	Andrew Stein	View Answer on Stackoverflow
Solution 13 - Bash	Mila Nautikus	View Answer on Stackoverflow
Solution 14 - Bash	JShorthouse	View Answer on Stackoverflow