how-to: one command for repeat OR iterate shell OR bash command delay OR interval

how-to: one command for repeat OR iterate shell OR bash command delay OR interval

[AD Marshall]

Is there already one bash command to do what the following script does (poorly or incompletely), ie repeat "command" indefinitely every "x" seconds:

#!/bin/sh
# usage: repeat [x] <command>
while true ; do $2 ; sleep $1 ; done


if not, and you want to use the above in a script of your own, just copy the above 3 lines and do the following (typing the lines into the console or pasting them in shell, using konsole under kde or gpm under a tty shell; hit <Ctrl-c> to stop it from looping). The two examples are optional. The stuff in angle brackets, <>, is stuff you won't see in your shell output:

am@[bin]$ cat >repeat
#!/bin/sh
# usage: repeat [x] <command>
while true ; do $2 ; sleep $1 ; done
am@[bin]$ chmod +x repeat
<examples>
am@[bin]$ ./repeat 2 "cat /proc/loadavg"
0.46 0.92 1.72 9/125 24171
0.46 0.92 1.72 2/125 24173
0.59 0.94 1.72 1/125 24181
<Ctrl-c>
am@[bin]$ cd ..
am@[~]$ repeat 2 uname
Linux
Linux
<Ctrl-c>

btw: i've already posted the same to:
http://www.linuxquestions.org/questions/showthread.php?s=&threadid=343892

some answers might show up there before i get back 

-- 
AD Marshall
Tel:  +84 (0)903871313
eM:   admarshall@gmail.com
Web:  http://h0lug.sourceforge.net
Zone: ICT (IndoChina Time; GMT/UTC+7)
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Re: how-to: one command for repeat OR iterate shell OR bash command delay OR interval

[John Kelly]

Hi,
On Sun, 17 Jul 2005 11:57:34 +0700
AD Marshall <admarshall@gmail.com> wrote:

> Is there already one bash command to do what the following script
> does (poorly or incompletely), ie repeat "command" indefinitely
> every "x" seconds:
> 
> #!/bin/sh
> # usage: repeat [x] <command>
> while true ; do $2 ; sleep $1 ; done
> 
> < rest deleted > 

The watch command might tbe what you want.
Or maybe not, if you don't want anything output to screen.
 
Try man watch for details.

regards,

John Kelly
 
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Re: how-to: one command for repeat OR iterate shell OR bash command delay OR interval

[AD Marshall]

On Sunday 17 July 2005 12:35, John Kelly wrote:
> Hi,
> On Sun, 17 Jul 2005 11:57:34 +0700
> AD Marshall <admarshall@gmail.com> wrote:
> 
> > Is there already one bash command to do what the following script
> > does (poorly or incompletely), ie repeat "command" indefinitely
> > every "x" seconds:
> > 
> > #!/bin/sh
> > # usage: repeat [x] <command>
> > while true ; do $2 ; sleep $1 ; done
> > 
> > < rest deleted > 
> 
> The watch command might tbe what you want.
> Or maybe not, if you don't want anything output to screen.
>  
> Try man watch for details.
> 
<cut>
Ya.  Thanks.  I'd (long) forgotten about "watch".  

but, actually, i should be more specific. what i'm trying to do is 
something like this -- though i'm screwing up on quoting or something

am@[~]$ repeat 2 "echo $(cat /proc/loadavg ; date +%H:%m:%S)"
0.05 0.14 0.24 6/127 27711 12:07:29
0.05 0.14 0.24 6/127 27711 12:07:29
0.05 0.14 0.24 6/127 27711 12:07:29

as you can see, only one instance of load average and time are repeated.
i want a running record that can be redirected to a file

i just tinkered with backslashes, back-quotes, double-quotes and 
single-quotes, but all the quoting stuff still confuses me.

and, imho, i would have thought someone would have written a simple 
tool to do this ages ago.  no?

thanx again,
andi

-- 
AD Marshall
Tel:  +84 (0)903871313
eM:   admarshall@gmail.com
Web:  http://h0lug.sourceforge.net
Zone: ICT (IndoChina Time; GMT/UTC+7)
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To unsubscribe from this list: send the line "unsubscribe linux-newbie" in
the body of a message to majordomo@vger.kernel.org
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Please read the FAQ at http://www.linux-learn.org/faqs

Re: how-to: one command for repeat OR iterate shell OR bash command delay OR interval

[AD Marshall]

my apologies, if necessary.  but it's way past lunchtime in saigon and
i'm STARVING.  i'll check back later.  thanx again. - best, andi

On Sunday 17 July 2005 13:07, AD Marshall wrote:
> On Sunday 17 July 2005 12:35, John Kelly wrote:
> > Hi,
> > On Sun, 17 Jul 2005 11:57:34 +0700
> > AD Marshall <admarshall@gmail.com> wrote:
> > 
> > > Is there already one bash command to do what the following script
> > > does (poorly or incompletely), ie repeat "command" indefinitely
> > > every "x" seconds:
> > > 
> > > #!/bin/sh
> > > # usage: repeat [x] <command>
> > > while true ; do $2 ; sleep $1 ; done
> > > 
> > > < rest deleted > 
> > 
> > The watch command might tbe what you want.
> > Or maybe not, if you don't want anything output to screen.
> >  
> > Try man watch for details.
> > 
> <cut>
> Ya.  Thanks.  I'd (long) forgotten about "watch".  
> 
> but, actually, i should be more specific. what i'm trying to do is 
> something like this -- though i'm screwing up on quoting or something
> 
> am@[~]$ repeat 2 "echo $(cat /proc/loadavg ; date +%H:%m:%S)"
> 0.05 0.14 0.24 6/127 27711 12:07:29
> 0.05 0.14 0.24 6/127 27711 12:07:29
> 0.05 0.14 0.24 6/127 27711 12:07:29
> 
> as you can see, only one instance of load average and time are repeated.
> i want a running record that can be redirected to a file
> 
> i just tinkered with backslashes, back-quotes, double-quotes and 
> single-quotes, but all the quoting stuff still confuses me.
> 
> and, imho, i would have thought someone would have written a simple 
> tool to do this ages ago.  no?
> 
> thanx again,
> andi
> 

-- 
AD Marshall
Tel:  +84 (0)903871313
eM:   admarshall@gmail.com
Web:  http://h0lug.sourceforge.net
Zone: ICT (IndoChina Time; GMT/UTC+7)
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To unsubscribe from this list: send the line "unsubscribe linux-newbie" in
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Please read the FAQ at http://www.linux-learn.org/faqs

[Solution] how-to: one command for repeat OR iterate shell OR bash command delay OR interval

[AD Marshall]

I worked out a cheap, if buggy, hack for what i wanted this morning.  But thanks all the same...  

In case you're interested:

am@[sh]$ rewatch 2 'cat /proc/loadavg'
0.51 0.36 0.65 1/121 9072 09:56:08
0.51 0.36 0.65 1/121 9083 09:56:10
0.47 0.36 0.65 1/121 9088 09:56:13

am@[sh]$ rewatch 2 'cat /proc/loadavg' 'mozilla' | tee rewatch-mozilla
0.43 0.35 0.65 1/121 9100 09:56:20
am       32106  0.0  0.3   3832   988 ?        S    07:37   0:00 /bin/sh /usr/bin/mozilla
am       32112 10.0 25.7 141688 66084 ?        Sl   07:37  13:54 /opt/mozilla/lib/mozilla-bin
0.40 0.34 0.64 3/121 9109 09:56:22
am       32106  0.0  0.3   3832   988 ?        S    07:37   0:00 /bin/sh /usr/bin/mozilla
am       32112 10.0 25.7 141688 66092 ?        Sl   07:37  13:54 /opt/mozilla/lib/mozilla-bin

am@[sh]$ cat ~/bin/rewatch
#!/bin/sh
# rewatch, v. 0.01
#
# Usage: rewatch <n> <cmdline> [process-to-watch]
#   n: seconds between repetitions
#   cmdline: command-line to repeat
#   process-to-watch: process for which "ps aux" info is to be displayed
#
# Purpose: repeat and, optionally, watch and record the "ps aux" info of
# that or any other process
#
# Bkgd: original purpose was to be able to input a command-line (in single
# quotes) along with an interval in seconds for its repetion and print a
# list of its stdouts labelled by the times they were printed until <Ctrl-c>
# is hit, and be able to capture all the output to stdout or a file.
#
# initial use was for watching and recording load averages as programs were
# loaded, eg, "re_watch 2 'cat /proc/loadavg' konqueror"
#
# Future: unknown
#
# Known Bugs: no input validation or user feedback for input errors
#
# Of course, bash operators will have to be properly quoted or escaped or
# not... -- which i still don't clearly understand

n=$1
cmdline=$2
proc2watch=$3

if test -z "$3"

then
  while true ; do echo $( $cmdline && echo "$( date +%H:%M:%S )" ) ; sleep $n ; done

else

while true ; do echo $( $cmdline && echo "$( date +%H:%M:%S )" ) ; echo "$( ps aux | grep -vE "(rewatch |grep |tee )" | grep $proc2watch )" ; sleep $n ; done

fi
am@[sh]$


On Sunday 17 July 2005 13:16, AD Marshall wrote:
> my apologies, if necessary.  but it's way past lunchtime in saigon and
> i'm STARVING.  i'll check back later.  thanx again. - best, andi
> 
> On Sunday 17 July 2005 13:07, AD Marshall wrote:
> > On Sunday 17 July 2005 12:35, John Kelly wrote:
> > > Hi,
> > > On Sun, 17 Jul 2005 11:57:34 +0700
> > > AD Marshall <admarshall@gmail.com> wrote:
> > > 
> > > > Is there already one bash command to do what the following script
> > > > does (poorly or incompletely), ie repeat "command" indefinitely
> > > > every "x" seconds:
> > > > 
> > > > #!/bin/sh
> > > > # usage: repeat [x] <command>
> > > > while true ; do $2 ; sleep $1 ; done
> > > > 
> > > > < rest deleted > 
> > > 
> > > The watch command might tbe what you want.
> > > Or maybe not, if you don't want anything output to screen.
> > >  
> > > Try man watch for details.
> > > 
> > <cut>
> > Ya.  Thanks.  I'd (long) forgotten about "watch".  
> > 
> > but, actually, i should be more specific. what i'm trying to do is 
> > something like this -- though i'm screwing up on quoting or something
> > 
> > am@[~]$ repeat 2 "echo $(cat /proc/loadavg ; date +%H:%m:%S)"
> > 0.05 0.14 0.24 6/127 27711 12:07:29
> > 0.05 0.14 0.24 6/127 27711 12:07:29
> > 0.05 0.14 0.24 6/127 27711 12:07:29
> > 
> > as you can see, only one instance of load average and time are repeated.
> > i want a running record that can be redirected to a file
> > 
> > i just tinkered with backslashes, back-quotes, double-quotes and 
> > single-quotes, but all the quoting stuff still confuses me.
> > 
> > and, imho, i would have thought someone would have written a simple 
> > tool to do this ages ago.  no?
> > 
> > thanx again,
> > andi
> > 
> 

-- 
AD Marshall
Tel:  +84 (0)903871313
eM:   admarshall@gmail.com
Web:  http://h0lug.sourceforge.net
Zone: ICT (IndoChina Time; GMT/UTC+7)
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To unsubscribe from this list: send the line "unsubscribe linux-newbie" in
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