The d command
Run make or other commands in the background, with output to a file.

223 Z% d c 'sleep 5 ; echo Hello folks'
[3] 3937
224 Z% 
[3]  + 3937 done       yostD_runCmd
224 Z% d sna
[ sleep 5 ; echo Hello folks ]
[3] 3965
225 Z% 
[3]  + 3965 done       yostD_runCmd
225 Z% qq
=dbegin 2006-07-08T16:28:11 PDT Sat
=dhost  Yost.com
=dwd    /Users/yost
=dcmd   sleep 5 ; echo Hello folks   
Hello folks
		  5.06 real         0.00 user         0.02 sys
=dstat  0
=dend   2006-07-08T16:28:17 PDT Sat
======= =======================================================================
=dbegin 2006-07-08T16:28:19 PDT Sat
=dhost  Yost.com
=dwd    /Users/yost
=dcmd   nice sleep 5 ; echo Hello folks    
Hello folks
		  5.06 real         0.00 user         0.02 sys
=dstat  0
=dend   2006-07-08T16:28:24 PDT Sat
======= =======================================================================
226 Z% d sp
sleep 5 ; echo Hello folks     
227 Z% d h
=dcmd   sleep 5 ; echo Hello folks   
=dstat  0
=dcmd   sleep 5 ; echo Hello folks    
=dstat  0
228 Z% 

# Source this file into sh, ksh, bash, or zsh
# See http://Yost.com/computers/d
#
# Needs the 'tac' command, which cats lines from end to beginning of file.
# Requires shell procedures.
#
# Bugs:
#  * Quoting arguments doesn't work properly.
#  * The background job is shown in a weird way, not showing the command(s)
#    you're really running.
#  * If you have a bad old shell, there won't be a job number handle on the 
#    backgrounded task
#
# The timing of commands could be better.
#
# I have tested this only with zsh 4.2.3
#
# Author: Dave@Yost.com
#   2.0 1991-04-xx
#   4.0 2004-12-19
#   5.0 2006-07-09
#   5.1 2006-07-10
#   5.2 2006-07-14
#   5.3 2006-12-14 fix "d s" bug when out file doesn't exist
#   5.4 2006-12-27 Make it work with bash, ksh, and sh

#-------------------------------------------------------------------------------

yostD_usage () {
  echo 1>&2 "
Usage: d [ -f <file> ] c[n][a][p] <cmd> <arg> ...
or:    d [ -f <file> ] m[n][a][p] [ <make-arg> ... ]
or:    d [ -f <file> ] s[n][a][p] [ <additional-arg> ... ]
or:    d [ -f <file> ] h

Do a task in the background, with its stdout and stderr redirected to
a file called 'out' or <file> or named by \$yostD_OUTFILE (environment variable).
The d command usually does
  mv ,out out
before creating a new out file but can be told to append to out instead.

The first argument to the d command is called the task argument.
The following letters in the task argument determine the task that is run:
  One of these is required:
    c - Do the following command - redirection and piping work (if escaped).
    m - Do a make.
    s - Do the same command again (extract the last command from <file>,
        and run it again (without 'nice' unless you ask for it again).
    h - Print a history of what happened in this out file (h by itself).
  These are optional:
    p - just print the command that would be executed; don't run it
    n - Do it 'nice'ly.
    a - Append to $yostD_OUTFILE

See http://Yost.com/computers/d
"
  return 2
}

#-------------------------------------------------------------------------------

d() {
  yostD_setOutFileVariableIfNotSet
  yostD_args "$@" \
  && \
  if [[ "$yostD_optPrint" = true ]] ; then
    yostD_print
  else
    yostD_run
  fi
}

#-------------------------------------------------------------------------------

yostD_setOutFileVariableIfNotSet() {
  if [[ -z "${yostD_OUTFILE:-}" ]] ; then yostD_OUTFILE=out ; fi
}

#-------------------------------------------------------------------------------

yostD_args() {

  yostD_optAppend=false
  yostD_optNice=
  yostD_optNicePrefix=
  yostD_optPrint=false
  yostD_optPrintAll=false
  yostD_optSame=false

  if [[ $# = 0 ]] ; then return $(yostD_usage) ; fi

  if [[ "${1:-}" = -f ]] ; then
    yostD_OUTFILE=$2
    shift
    shift
  fi

  yostD_task=$1
  shift

  # There must be exactly one command.

  case "$yostD_task" in
  ""|*[\`~!@#$%^\&*\(\)_-+={[}\]|\\:\;'"'"'"\<,\>.?/bdefgijkloqrtuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ]*)
    return $(yostD_usage)
    ;;
  h)
    yostD_optPrint=true
    yostD_optPrintAll=true
    ;;
  *c*m* | *m*c* | *c*s* | *s*c* | *m*s* | *s*m* )
    return $(yostD_usage)
    ;;
  *c*)
    if [[ $# = 0 ]] ; then
      return $(yostD_usage)
    else
      yostD_cmd="$@"
    fi
    ;;
  *m*)
    yostD_cmd=make
    if [[ -n "$@" ]] ; then
      yostD_cmd="$yostD_cmd $@"
    fi
    ;;
  *s*)
    yostD_optSame=true
    yostD_cmd="$(yostD_findSameCmd)"
    if [[ $? != 0 ]] ; then
      return 2
    fi
    if [[ -n "$@" ]] ; then
      # Shell syntax.  Hrmph.
      #if [[ $1 = ${yostD_cmd[1]} ]] ; then
      #  echo 1>&2 "d: extra args to s are probably wrong"
      #  return 2
      #fi
      yostD_cmd="$yostD_cmd $@"
    fi
    ;;
  *)
    return $(yostD_usage)
  esac

  # And there can be optional modifiers.
  
  case "$yostD_task" in
  *a*)
    yostD_optAppend=true
  esac

  case "$yostD_task" in
  *n*)
    yostD_optNice="nice"
    yostD_optNicePrefix="nice "
  esac

  case "$yostD_task" in
  *p*)
    yostD_optPrint=true
  esac

  return $(yostD_ensureShellSet)
}

#-------------------------------------------------------------------------------

yostD_findSameCmd() {
  if [[ ! -r $yostD_OUTFILE ]] ; then
    echo 1>&2 "d: can't run same command again; can't read file '$yostD_OUTFILE'"
    return 2
  fi
  yostD_cmd=$(
    tac $yostD_OUTFILE 2> /dev/null \
    | sed -n '
        /^=dcmd *nice  */{
          s///p
          q
        }
        /^=dcmd  */{
          s///p
          q
        }
      '
  )
  if [[ -z "$yostD_cmd" ]] ; then
    echo 1>&2 "d: can't run same command again; can't find usable command in file '$yostD_OUTFILE'"
    return 2
  fi
  echo "$yostD_cmd"
}

#-------------------------------------------------------------------------------

yostD_ensureShellSet() {
  if [[ -n "$SHELL:-" ]] ; then
       SHELL=$(which zsh) \
    || SHELL=$(which bash) \
    || SHELL=$(which ksh) \
    || SHELL=$(which sh) \
    || (
      echo 1>&2 "d: Can't operate because you have no SHELL environment variable"
      return 2
    )
  fi
}

#-------------------------------------------------------------------------------

yostD_print() {
  if [[ "$yostD_optPrintAll" = true ]] ; then
    sed -n '
        /^=dcmd/p
        /^=dstat/p
        ' $yostD_OUTFILE
  else
    echo ${yostD_optNicePrefix}$yostD_cmd
  fi
  return 0
}

#-------------------------------------------------------------------------------

yostD_run() {
  if [[ "$yostD_optSame"    = true ]] ; then
    echo 1>&2 "[ $(yostD_print) ]"
  fi
  if [[ "$yostD_optAppend" != true ]] ; then
    yostD_mvOutFile
  fi \
  && \
  yostD_runCmd &
}

#-------------------------------------------------------------------------------

yostD_mvOutFile() {
  mv -f $yostD_OUTFILE $(yostD_mkBackupName "${yostD_OUTFILE:-out}") 2> /dev/null
  echo -n '' >> $yostD_OUTFILE
}

#-------------------------------------------------------------------------------

yostD_runInternal() {
  if [[ -n "$yostD_optNice" ]] ; then
    time $yostD_optNice $SHELL -c "$yostD_cmd"
  else
    time                $SHELL -c "$yostD_cmd"
  fi
}

yostD_runCmd() {
  {
    # We use sh -c so pipes and semcolons work.
    yostD_outputPrologue \
    && \
    runInternal
    yostD_outputEpilogue
    yostD_beep
  } \
  >> $yostD_OUTFILE 2>&1
}

#-------------------------------------------------------------------------------

yostD_outputPrologue() {
  echo '=dbegin '$(yostD_formattedDate)"
=dhost  ${HOST:-$(hostname)}
=dwd    $(pwd)
=dcmd   ${yostD_optNicePrefix}$yostD_cmd"
}

#-------------------------------------------------------------------------------

yostD_outputEpilogue() {
  echo "=dstat  $?
=dend   "`yostD_formattedDate`"
======= ======================================================================="
}

#-------------------------------------------------------------------------------

yostD_beep() {
  printf "\b" > /dev/tty
}

#-------------------------------------------------------------------------------

yostD_formattedDate() {
  date '+%Y-%m-%dT%H:%M:%S %Z %a'
}


#-------------------------------------------------------------------------------

yostD_mkBackupName() {
  echo ,"$1"
}

#===============================================================================

# Also useful:
# j() { jobs "$@" ; }
# k() { kill %%   ; }

if ! type q   \
&& ! type qq  \
&& ! type qt  \
&& ! type cq  \
&& ! type cqq \
&& ! type wq  \
&& ! type wqt \
&& ! type mvout ; then
  yostD_qOK=true
else
  yostD_qOK=
fi > /dev/null 2>&1

if [[ $yostD_qOK = true ]] ; then
  q    () { tail -f  ${yostD_OUTFILE:-out} ; }
  qq   () { cat      ${yostD_OUTFILE:-out} ; }
  qt   () { tail -20 ${yostD_OUTFILE:-out} ; }
  cq   () { clear                   ; q  ; }
  cqq  () { clear                   ; qq ; }
  wq   () { wait "$@" ; printf "\b" ; qq ; }
  wqt  () { wait "$@" ; printf "\b" ; qt ; }
  mvout() { mv -f ${yostD_OUTFILE:-out} $(yostD_mkBackupName "${yostD_OUTFILE:-out}") ; }
else
  echo 1>&2 "d.sh can't create the 'd' helper commands because of conflicts"
fi

#-------------------------------------------------------------------------------

# Copyright 2006 Dave Yost <Dave@Yost.com>
# This version is
#   d.sh 5.4 2006-12-27
# which at time of this publication can be found at:
#   http://Yost.com/computers/d
# Redistribution and use in the form of source code or derivative data built 
# from the source code, with or without modification, are permitted provided 
# that the following conditions are met:
# 1. THE USER AGREES THAT THERE IS NO WARRANTY.
# 2. If and only if appropriate, the above phrase "This version is" must be 
#    followed by the phrase "a modified form of" or "extracted from" or 
#    "extracted and modified from".
# 3. Redistributions of source code must retain this notice intact.
# 4. Redistributions in the form of derivative data built from the source 
#    code must reproduce this notice intact in the documentation and/or other 
#    materials provided with the distribution, and each file in the derivative 
#    data must reproduce any Yost.com URI included in the original distribution.
# 5. Neither the name of Dave Yost nor the names of its contributors may be 
#    used to endorse or promote products derived from this software without 
#    specific prior written permission.
# This notice comprises all text from "Copyright" above through the end of 
# this sentence.