(old)Puppy Linux Discussion Forum

puppyluvr wrote: case
*
*
*
esac

#!/bin/sh
case
xdotool mousemove 20 20 
sleep 3
xdotool mousemove 20 40
sleep 1
esac

#!/bin/sh
x=10
if x <11 then
xdotool mousemove 20 20 
sleep 3
xdotool mousemove 20 40
sleep 1
 fi 

technosaurus wrote: while :; do
#infinite loop unless "break" is called
done

simargl wrote:

Code: Select all

while true; do sleep 1 && echo ""; done

#!/bin/sh
while true; do sleep 1 && echo ""; done
xdotool mousemove 20 20 
sleep 3
xdotool mousemove 20 40
sleep 1

simargl wrote:

Code: Select all

#!/bin/sh
while true; do
xdotool mousemove 20 20
sleep 3
xdotool mousemove 20 40
sleep 1
done

technosaurus wrote:also there should be an example in the xdotool thread that I wrote months ago that was designed to intentionally shake the mouse randomly to be annoying

technosaurus wrote:annoying mouse fun

Code: Select all

while :; do xdotool mousemove_relative -- -$(($RANDOM % 10)) $(($RANDOM % 10)); xdotool mousemove_relative -- $(($RANDOM % 10)) -$(($RANDOM % 10)); done

Code: Select all

....long pipe |cat `: inline comments`| \
continuation |cat `: inline comments`| \
...

here cat just acts as a pass through...but really most of the really long pipes you come across could be reimplemented much faster in a couple lines of awk (learn shell first though ... it will help)

Karl Godt wrote:A while or until loop needs to be programmed with some sleep lines as stated above. Otherwise they would run inside commands as fast as possible, heating up your cpu.

Code: Select all

until [ "`pidof poweroff`" -o "`pidof reboot`" ]; do
yes
done

#!/bin/sh
until [ "`pidof poweroff`" -o "`pidof reboot`" ]; do
xdotool mousemove 20 20
sleep 3
xdotool mousemove 20 40
sleep 3
yes
done

greengeek wrote:This moves the moves the mouse as expected but does not loop. Have I copied it wrongly?

Code: Select all

#!/bin/sh
until [ "`pidof poweroff`" -o "`pidof reboot`" ]; do
xdotool mousemove 20 20
sleep 3
xdotool mousemove 20 40
sleep 3
yes
done

:(){ echo "Loop..."; sleep 1; :; };:

http://www.manpages.spotlynx.com/solaris/man/yes.1 wrote:yes can be used to respond programatically to programs that require an interactive response.

greengeek wrote:How easy is it to explain what you mean by the "fork bomb". Can you clarify the danger you refer to or if I google it will I be likely to find the explanation (without drawing the attention of Echelon and Homeland Security)?

SFR wrote:infinite loop, but deprived of deadly "fork" mechanism) can be utilized as well:

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:(){ echo "Loop..."; sleep 1; :; };:

But of course this is not a good idea to have something like that in your code, so consider this as a "tip of the day".

SFR wrote:Basically it's a nice looking one-liner, which multiplies itself (or rather its own process) ad infinitum, what makes system completely freezed.
Sadly, Puppy isn't immune for that kind of attack..!

As a fork bomb's mode of operation is entirely encapsulated by creating new processes, one way of preventing a fork bomb from severely affecting the entire system is to limit the maximum number of processes that a single user may own.

greengeek wrote:

SFR wrote:infinite loop, but deprived of deadly "fork" mechanism) can be utilized as well:

Code: Select all

:(){ echo "Loop..."; sleep 1; :; };:

But of course this is not a good idea to have something like that in your code, so consider this as a "tip of the day".

Do you mean that it's not a good idea because it's so easy to get it wrong (and include a recursive fork by mistake)?

greengeek wrote:Wiki suggests this as a means of prevention:

As a fork bomb's mode of operation is entirely encapsulated by creating new processes, one way of preventing a fork bomb from severely affecting the entire system is to limit the maximum number of processes that a single user may own.

I wonder if this might be possible on Puppy.

# ulimit -a | grep "max user processes"
max user processes (-u) 30948
#

SFR wrote:Hard to say...

# ulimit -a | grep "max user processes"
max user processes (-u) 30948
#

shows that max. number of processes is limited, but it doesn't seem to work (maybe it doesn't affect root account?).
Greetings!

This works and prevents root user from starting more than 50 processes.

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root   hard    nproc           50

greengeek wrote:On a different thread "scientist" has been trying the following:

This works and prevents root user from starting more than 50 processes.

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root   hard    nproc           50

I haven't tried it yet but thought I would post it.

# root   hard    nproc           50
bash: root: command not found
#