How to get the start time of a long-running Linux process

Question

Is it possible to get the start time of an old running process  It seems that ps will report the date  not the time  if it wasn t started today  and only the year if it wasn t started this year  Is the precision lost forever for old processes

User · Answer

The ps command  at least the procps version used by many Linux distributions  has a number of format fields that relate to the process start time  including lstart which always gives the full date and time the process started     ps -p 1 -wo pid lstart cmd   PID                  STARTED CMD     1 Mon Dec 23 00 31 43 2013  sbin init    ps -p 1 -p    -wo user pid  cpu  mem vsz rss tty stat lstart cmd USER       PID  CPU  MEM    VSZ   RSS TT       STAT                  STARTED CMD root         1  0 0  0 1   2800  1152          Ss   Mon Dec 23 00 31 44 2013  sbin init root      5151  0 3  0 1   4732  1980 pts 2    S    Sat Mar  8 16 50 47 2014 bash   For a discussion of how the information is published in the  proc filesystem  see https   unix stackexchange com questions 7870 how-to-check-how-long-a-process-has-been-running   In my experience under Linux  the time stamp on the  proc  directories seem to be related to a moment when the virtual directory was recently accessed rather than the start time of the processes     date  ls -ld  proc 1  proc     Sat Mar  8 17 14 21 EST 2014 dr-xr-xr-x 7 root root 0 2014-03-08 16 50  proc 1 dr-xr-xr-x 7 root root 0 2014-03-08 16 51  proc 5151   Note that in this case I ran a  ps -p 1  command at about 16 50  then spawned a new bash shell  then ran the  ps -p 1 -p     command within that shell shortly afterward

User · Answer

ps -eo pid cmd lstart   grep YOUR-PID-HERE

User · Answer

ls -ltrh  proc   grep YOUR-PID-HERE   For example  my Google Chrome s PID is 11583   ls -l  proc   grep 11583 dr-xr-xr-x  7 adam       adam                     0 2011-04-20 16 34 11583

User · Answer

As a follow-up to Adam Matan s answer  the  proc  lt pid gt  directory s time stamp as such is not necessarily directly useful  but you can use  awk -v RS      END print  20    proc 12345 stat   to get the start time in clock ticks since system boot 1  This is a slightly tricky unit to use  see also convert jiffies to seconds for details   awk -v ticks    getconf CLK TCK    NR  1   now  1  next       END   printf   9 0f n   now -   20 ticks      proc uptime RS      proc 12345 stat   This should give you seconds  which you can pass to strftime   to get a  human-readable  or otherwise  timestamp   awk -v ticks    getconf CLK TCK    NR  1   now  1  next       END   print strftime   c   systime   -  now-  20 ticks        proc uptime RS      proc 12345 stat   Updated with some fixes from Stephane Chazelas in the comments  thanks as always   If you only have Mawk  maybe try  awk -v ticks    getconf CLK TCK   -v epoch    date   s       NR  1   now  1  next     END   printf   9 0f n   epoch -  now-  20 ticks       proc uptime RS      proc 12345 stat   xargs -i date -d         1 man proc  search for starttime

User · Answer

You can specify a formatter and use lstart  like this command   ps -eo pid lstart cmd   The above command will output all processes  with formatters to get PID  command run  and date time started   Example  from Debian Jessie command line     ps -eo pid lstart cmd   PID CMD                                          STARTED     1 Tue Jun  7 01 29 38 2016  sbin init                       2 Tue Jun  7 01 29 38 2016  kthreadd                        3 Tue Jun  7 01 29 38 2016  ksoftirqd 0                     5 Tue Jun  7 01 29 38 2016  kworker 0 0H                    7 Tue Jun  7 01 29 38 2016  rcu sched                       8 Tue Jun  7 01 29 38 2016  rcu bh                          9 Tue Jun  7 01 29 38 2016  migration 0                    10 Tue Jun  7 01 29 38 2016  kdevtmpfs                      11 Tue Jun  7 01 29 38 2016  netns                         277 Tue Jun  7 01 29 38 2016  writeback                     279 Tue Jun  7 01 29 38 2016  crypto                                  You can read ps s manpage or check Opengroup s page for the other formatters

User · Answer

ps -eo pid etime cmd sort -n -k2

[linux] How to get the start time of a long-running Linux process?

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