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

Question

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]$ sl         


        

Answer 1

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

Answer 2

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

Answer 3

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

Answer 4

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: ${timer_show}s][\w]$ '

Answer 5

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
}

Answer 6

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
$