> Am 22.06.2016 um 11:34 schrieb John Lawlor <jo...@openet.com>: > > Hi, > > I came across some unusual behaviour in bash using the ‘-c’ parameter. > > If I do the following: > > bash -c "ping 127.0.0.1 > $HOME/console.log" & > > This starts two processes bash and ping: > > john 18038 17951 0 09:26 pts/14 00:00:00 bash -c ping 127.0.0.1 > > /home/john/console.log > john 18039 18038 0 09:26 pts/14 00:00:00 ping 127.0.0.1 > > From the process hierarchy bash is the parent process of ping. > > Now if I kill bash: > > kill -15 18038
This kills just the specified process. What does happen when you issue: $ kill %1 (resp. the the number output when issuing the above command) instead? -- Reuti > And check the process tree again: > > UID PID PPID C STIME TTY TIME CMD > john 17951 30467 0 09:25 pts/14 00:00:00 /bin/bash > john 18039 1 0 09:26 pts/14 00:00:00 ping 127.0.0.1 > john 18064 17951 0 09:30 pts/14 00:00:00 ps -f > [1]+ Terminated bash -c "ping 127.0.0.1 > $HOME/console.log" > > Bash is killed but not the child ping process. I was expecting that to be > killed also. > > If I repeat the exact same steps with ksh –c, it does kill the ping process. > > It looks like bash does a double fork or something whereas ksh does only an > execute without fork. > > Regards, > John > > This email and any files transmitted with it are confidential and intended > solely for the use of the individual or entity to whom they are addressed. If > you are not the intended recipient, please note that any review, > dissemination, disclosure, alteration, printing, circulation, retention or > transmission of this e-mail and/or any file or attachment transmitted with > it, is prohibited and may be unlawful. If you have received this e-mail or > any file or attachment transmitted with it in error please notify > postmas...@openet.com. Although Openet has taken reasonable precautions to > ensure no viruses are present in this email, we cannot accept responsibility > for any loss or damage arising from the use of this email or attachments.
