# Linux - pause and resume a process with signal ###### tags: `linux` Example to pause a file copy process and resume it. ###### run a rsync with bandwidth limit to 1MB to copy file ``` [12:39:26] ycheng@nuc8:~/Downloads $ rsync --bwlimit=1000 -P ./ubuntu-22.04-live-server-amd64.iso /mnt/data/ ubuntu-22.04-live-server-amd64.iso 3,178,496 0% 1000.98kB/s 0:24:22 ``` ###### get main pid of the rsync process ``` [15:01:56] ycheng@nuc8:~ $ ps -elf | grep rsync 0 S ycheng 6111 13386 0 80 0 - 3883 poll_s 10:25 pts/0 00:00:00 rsync --bwlimit=1000 -P ./ubuntu-22.04-live-server-amd64.iso /mnt/data/ 1 S ycheng 6112 6111 0 80 0 - 3811 poll_s 10:25 pts/0 00:00:00 rsync --bwlimit=1000 -P ./ubuntu-22.04-live-server-amd64.iso /mnt/data/ 1 S ycheng 6113 6112 0 80 0 - 3876 poll_s 10:25 pts/0 00:00:00 rsync --bwlimit=1000 -P ./ubuntu-22.04-live-server-amd64.iso /mnt/data/ 0 S ycheng 6475 26401 0 80 0 - 3692 pipe_w 10:26 pts/14 00:00:00 grep --color=auto rsync ``` > Here there are 3 process threads to the rsync, the 6111 is parent process. ###### sent SIGSTOP signal to the process ``` [15:01:56] ycheng@nuc8:~ $ kill -STOP 6111 ``` ###### the rsync process "Stopped" and move to background. ``` [12:39:26] ycheng@nuc8:~/Downloads $ rsync --bwlimit=1000 -P ./ubuntu-22.04-live-server-amd64.iso /mnt/data/ ubuntu-22.04-live-server-amd64.iso 119,570,432 8% 1000.49kB/s 0:22:26 [1]+ Stopped rsync --bwlimit=1000 -P ./ubuntu-22.04-live-server-amd64.iso /mnt/data/ ``` ###### sent SIG ``` [15:01:56] ycheng@nuc8:~ $ kill -SIGCONT 6111 ``` ###### bring the rsync progress back to foreground ``` [12:39:26] ycheng@nuc8:~/Downloads $ fg rsync --bwlimit=1000 -P ./ubuntu-22.04-live-server-amd64.iso /mnt/data/ 152,895,488 10% 1000.49kB/s 0:21:53 ``` #### Notes - you could also use "ctrl" + "z" to stop process if you have terminal running the process. - use "jobs" command to list process in background - could use "fg" command to continue #### Reference https://unix.stackexchange.com/questions/502065/is-there-a-way-to-pause-a-running-process-on-linux-systems-and-resume-later