Pause a running script in Mac terminal and then resume later

问题:

How can I 'pause' (not stop) a running script from terminal in OSX, to resume it later from the point it paused.

回答1:

To complement @devnull and @DavidW's helpful answers:
Here are convenience functions for suspending (pausing) / resuming a script by name, from any shell (not just the one that started the script):

Pass the script's filename(s) (without path):

suspend-script someScript ...

and later:

resume-script someScript ...

Update: Added additional function for killing a script by name: kill-script someScript ...

• Works with scripts run by either bash or sh (which is effectively just a bash alias on OSX).
• If multiple instances of a script are running, only the most recently started is targeted.
• Exit code will be non-zero in case of failure (including not finding a running script by the given name).
• suspend-script and resume-script: if a script process is already in the desired state, no operation is performed (and no error is reported).

Functions (e.g., place them in ~/.bash_profile):

suspend-script() {   [[ -z $1 || $1 == '-h' || $1 == '--help' ]] && { echo "Usage: $FUNCNAME scriptFileName ..."$'\n'"Suspends the specified bash/sh script(s)."; return $(( ${#1} == 0 )); }   local ec=0   for p in "$@"; do     pkill -STOP -nf '/?(bash|sh)[ ]+(.*/)?'"$p"'( |$)' \       && echo "'$1' suspended." \       || { ec=$?; echo "ERROR: bash/sh script process not found: '$p'" 1>&2; }   done   return $ec }  resume-script() {   [[ -z $1 || $1 == '-h' || $1 == '--help' ]] && { echo "Usage: $FUNCNAME scriptFileName ..."$'\n'"Resumes the specified bash/sh script(s)."; return $(( ${#1} == 0 )); }   local ec=0   for p in "$@"; do     pkill -CONT -nf '/?(bash|sh)[ ]+(.*/)?'"$p"'( |$)' \      && echo "'$1' resumed." \      || { ec=$?; echo "ERROR: bash/sh script process not found: '$p'" 1>&2; }   done   return $ec }  kill-script() {   [[ -z $1 || $1 == '-h' || $1 == '--help' ]] && { echo "Usage: $FUNCNAME scriptFileName ..."$'\n'"Kills the specified bash/sh script(s)."; return $(( ${#1} == 0 )); }   local ec=0   for p in "$@"; do     pkill -nf '/?(bash|sh)[ ]+(.*/)?'"$p"'( |$)' \      && echo "'$1' killed." \      || { ec=$?; echo "ERROR: bash/sh script process not found: '$p'" 1>&2; }   done   return $ec } 

回答2:

If you're using BASH as the shell (which is the default shell on a Mac), you can use BASH's built in job control capabilities.

If the script is running in the foreground of your terminal, you can press Control-Z to pause the script. This will suspend the running of the script.

To restart it, type jobs and you'll see the suspended job listed there. Type fg or more specific fg %x where x is the number of the suspended job.

$ test.pl   # Test script (prints out Foo every two seconds Foo! Foo! ^Z $  # Job has been suspended $ jobs [1] + Stopped                  ./test.pl $ fg %1  #Restarts Job #1 Foo! 

The Control-Z key that suspends the job is the default, but could be modified. The stty can change this and will show you the current default:

$ stty -a      speed 9600 baud; 40 rows; 120 columns; lflags: icanon isig iexten echo echoe -echok echoke -echonl echoctl         -echoprt -altwerase -noflsh -tostop -flusho pendin -nokerninfo         -extproc iflags: -istrip icrnl -inlcr -igncr ixon -ixoff ixany imaxbel iutf8         -ignbrk brkint -inpck -ignpar -parmrk oflags: opost onlcr -oxtabs -onocr -onlret cflags: cread cs8 -parenb -parodd hupcl -clocal -cstopb -crtscts -dsrflow         -dtrflow -mdmbuf cchars: discard = ^O; dsusp = ^Y; eof = ^D; eol = <undef>;         eol2 = <undef>; erase = ^H; intr = ^C; kill = ^U; lnext = ^V;         min = 1; quit = ^\; reprint = ^R; start = ^Q; status = ^T;         stop = ^S; susp = ^Z; time = 0; werase = ^W; 

You can see the very last line has susp = ^Z. This is the key that will suspend your script. In this case, it's Control-Z.

You can also use the bg command to make a suspended job run in the background. However, that background job will terminate when you close the shell/Terminal Window unless you had prepended nohup to the front of the command.

回答3:

Find the process ID of the running script.

To stop (or what you refer to as pause) the script, say:

kill -SIGSTOP PID 

To resume the stopped (or paused) process, say:

kill -SIGCONT PID 

(where PID refers to the numeric process ID.)

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