simple shell script question

[bruce]

trying to get the following to output
  pgrep -f 'bash' | wc -l

the var $xx has the cmd...
  something's missing to allow the backtics to run the cmd..
  if the cmd is hadcoded.run, it works..

can't see what the homer simpson "doh" moment is!

thanks

#!/bin/bash
#
# ptest.sh
#
# use predefined variables to access passed arguments
#
# $1
aa=$1
aa='bash'
echo $aa " pp"
xx="pgrep -f '"${aa}"' | wc -l"
echo $xx   <<< this dsplays the test pgrep
echo `$xx`   <<  err msg
echo `${xx}`  << err msg...

## trying to get -- pgrep -f 'bash' | wc -l <<
## i'm getting a Usage: pgrep [....] err msg..

[Gordon Messmer]

On 08/09/2017 05:47 PM, bruce wrote:
> aa='bash'
> xx="pgrep -f '"${aa}"' | wc -l"
> echo $xx   <<< this dsplays the test pgrep
> echo `$xx`   <<  err msg
> echo `${xx}`  << err msg...

eval "$xx"

or:

echo $(eval "$xx")

In the invocation you're trying to use, "|" is being passed as an 
argument to pgrep, rather than creating a pipe between commands/processes.

[kevin martin]

unclear what you are trying to accomplish here.  If, for example, you are
trying to pgrep for all processes that have 'bash' in the process name:
#!/bin/bash
aa='bash'
xx="pgrep -f ${aa} | wc -l"
echo $xx <<< shows the command in $xx
eval ${xx} <<< runs the command in $xx

---

Regards,

Kevin Martin

On Wed, Aug 9, 2017 at 7:47 PM, bruce  wrote:
> trying to get the following to output
>   pgrep -f 'bash' | wc -l
>
> the var $xx has the cmd...
>   something's missing to allow the backtics to run the cmd..
>   if the cmd is hadcoded.run, it works..
>
> can't see what the homer simpson "doh" moment is!
>
> thanks
>
> #!/bin/bash
> #
> # ptest.sh
> #
> # use predefined variables to access passed arguments
> #
> # $1
> aa=$1
> aa='bash'
> echo $aa " pp"
> xx="pgrep -f '"${aa}"' | wc -l"
> echo $xx   <<< this dsplays the test pgrep
> echo `$xx`   <<  err msg
> echo `${xx}`  << err msg...
>
> ## trying to get -- pgrep -f 'bash' | wc -l <<
> ## i'm getting a Usage: pgrep [....] err msg..
> _______________________________________________
> users mailing list -- [e-mail]
> To unsubscribe send an email to [e-mail]

[Rick Stevens]

On 08/09/2017 05:47 PM, bruce wrote:
> trying to get the following to output
>   pgrep -f 'bash' | wc -l
>
> the var $xx has the cmd...
>   something's missing to allow the backtics to run the cmd..
>   if the cmd is hadcoded.run, it works..
>
> can't see what the homer simpson "doh" moment is!

It's kind of silly to pass that through "wc". Just use the "-c"
option to pgrep:

[root@prophead ~]# ps ax | grep bash | grep -v grep | wc -l
28
[root@prophead ~]# pgrep -f bash | wc -l
28
[root@prophead ~]# pgrep -c -f bash
28

I think PHP actually tacks on a blank line when executing the stuff in a
backtick, so the "wc" value will always be 1 greater than the normal
return. That's just a guess from doing a var_dump() on the output of the
command:

[root@prophead ~]# php -a
    Interactive shell

php > var_dump(`pgrep -f bash | wc -l`);
    string(3) "29
    "
    php > exit
    [root@prophead ~]#
> #!/bin/bash
> #
> # ptest.sh
> #
> # use predefined variables to access passed arguments
> #
> # $1
> aa=$1
> aa='bash'
> echo $aa " pp"
> xx="pgrep -f '"${aa}"' | wc -l"
> echo $xx   <<< this dsplays the test pgrep
> echo `$xx`   <<  err msg
> echo `${xx}`  << err msg...
>
> ## trying to get -- pgrep -f 'bash' | wc -l <<
> ## i'm getting a Usage: pgrep [....] err msg..
> _______________________________________________
> users mailing list -- [e-mail]
> To unsubscribe send an email to [e-mail]

[bruce]

hmmmm   update..

this works...
aa='bash'
echo $aa " pp"
xx= pgrep -f $aa | wc -l
echo $xx

however, I can't seem to figure out how to enclose the aa var in
single quotes within the pgrep.

thoughts/comments..

thanks

On Wed, Aug 9, 2017 at 8:47 PM, bruce  wrote:
> trying to get the following to output
>   pgrep -f 'bash' | wc -l
>
> the var $xx has the cmd...
>   something's missing to allow the backtics to run the cmd..
>   if the cmd is hadcoded.run, it works..
>
> can't see what the homer simpson "doh" moment is!
>
> thanks
>
> #!/bin/bash
> #
> # ptest.sh
> #
> # use predefined variables to access passed arguments
> #
> # $1
> aa=$1
> aa='bash'
> echo $aa " pp"
> xx="pgrep -f '"${aa}"' | wc -l"
> echo $xx   <<< this dsplays the test pgrep
> echo `$xx`   <<  err msg
> echo `${xx}`  << err msg...
>
> ## trying to get -- pgrep -f 'bash' | wc -l <<
> ## i'm getting a Usage: pgrep [....] err msg..

[kevin martin]

is the end result meant to be able to pass some string ($1) to pgrep that
get's counted?  knowing what you're trying to accomplish would make it
easier to help.

---

Regards,

Kevin Martin

On Wed, Aug 9, 2017 at 8:24 PM, bruce  wrote:
> hmmmm   update..
>
> this works...
> aa='bash'
> echo $aa " pp"
> xx= pgrep -f $aa | wc -l
> echo $xx
>
> however, I can't seem to figure out how to enclose the aa var in
> single quotes within the pgrep.
>
> thoughts/comments..
>
> thanks
>
> On Wed, Aug 9, 2017 at 8:47 PM, bruce  wrote:
> > trying to get the following to output
> >   pgrep -f 'bash' | wc -l
> >
> > the var $xx has the cmd...
> >   something's missing to allow the backtics to run the cmd..
> >   if the cmd is hadcoded.run, it works..
> >
> > can't see what the homer simpson "doh" moment is!
> >
> > thanks
> >
> > #!/bin/bash
> > #
> > # ptest.sh
> > #
> > # use predefined variables to access passed arguments
> > #
> > # $1
> > aa=$1
> > aa='bash'
> > echo $aa " pp"
> > xx="pgrep -f '"${aa}"' | wc -l"
> > echo $xx   <<< this dsplays the test pgrep
> > echo `$xx`   <<  err msg
> > echo `${xx}`  << err msg...
> >
> > ## trying to get -- pgrep -f 'bash' | wc -l <<
> > ## i'm getting a Usage: pgrep [....] err msg..
>
> users mailing list -- [e-mail]
> To unsubscribe send an email to [e-mail]

[bruce]

On Wed, Aug 9, 2017 at 9:52 PM, kevin martin  wrote:
> is the end result meant to be able to pass some string ($1) to pgrep that
> get's counted?  knowing what you're trying to accomplish would make it
> easier to help.

-------------

hey kevin. sorry.

the test was to (1) replicate the results I get from the cmdline.
and to then (2) be able to pass a input/var to then generate the pgrep
count results

the initial cmdline pgrep  -- pgrep -f 'bash' | wc -l
 -- on the test box, this returns a "50" count

in testing using php/bash -- i get a "51"

#!/bin/bash -f
#
# ptest.sh
#

pgrep -f 'bash' | wc -l

------------------------------------

on the test centos box, there is no pgrep -c << option.. haven't
checked the fedora yet

however, if i replace "bash" with a procname that doesn't exist.. it
correctly returns "0"..

So, I was/am trying to wrap my head around what's going on.

thanks
> Regards,
>
> Kevin Martin
>
> On Wed, Aug 9, 2017 at 8:24 PM, bruce  wrote:
> > hmmmm   update..
> >
> > this works...
> > aa='bash'
> > echo $aa " pp"
> > xx= pgrep -f $aa | wc -l
> > echo $xx
> >
> > however, I can't seem to figure out how to enclose the aa var in
> > single quotes within the pgrep.
> >
> > thoughts/comments..
> >
> > thanks
> >
> > On Wed, Aug 9, 2017 at 8:47 PM, bruce  wrote:
> > > trying to get the following to output
> > >   pgrep -f 'bash' | wc -l
> > >
> > > the var $xx has the cmd...
> > >   something's missing to allow the backtics to run the cmd..
> > >   if the cmd is hadcoded.run, it works..
> > >
> > > can't see what the homer simpson "doh" moment is!
> > >
> > > thanks
> > >
> > > #!/bin/bash
> > > #
> > > # ptest.sh
> > > #
> > > # use predefined variables to access passed arguments
> > > #
> > > # $1
> > > aa=$1
> > > aa='bash'
> > > echo $aa " pp"
> > > xx="pgrep -f '"${aa}"' | wc -l"
> > > echo $xx   <<< this dsplays the test pgrep
> > > echo `$xx`   <<  err msg
> > > echo `${xx}`  << err msg...
> > >
> > > ## trying to get -- pgrep -f 'bash' | wc -l <<
> > > ## i'm getting a Usage: pgrep [....] err msg..
> >
> > users mailing list -- [e-mail]
> > To unsubscribe send an email to [e-mail]
>
> users mailing list -- [e-mail]
> To unsubscribe send an email to [e-mail]

[bruce]

hey guys...

appears to be user error... looks like i was on the wrong/older box..
on the updated centos/fed.. looks as i expected... at least for now!

thanks..

On Wed, Aug 9, 2017 at 10:07 PM, bruce  wrote:
> On Wed, Aug 9, 2017 at 9:52 PM, kevin martin  wrote:
> > is the end result meant to be able to pass some string ($1) to pgrep that
> > get's counted?  knowing what you're trying to accomplish would make it
> > easier to help.
>
> hey kevin. sorry.
>
> the test was to (1) replicate the results I get from the cmdline.
> and to then (2) be able to pass a input/var to then generate the pgrep
> count results
>
> the initial cmdline pgrep  -- pgrep -f 'bash' | wc -l
>  -- on the test box, this returns a "50" count
>
> in testing using php/bash -- i get a "51"
>
> #!/bin/bash -f
> #
> # ptest.sh
> #
>
> pgrep -f 'bash' | wc -l
>
> on the test centos box, there is no pgrep -c << option.. haven't
> checked the fedora yet
>
> however, if i replace "bash" with a procname that doesn't exist.. it
> correctly returns "0"..
>
> So, I was/am trying to wrap my head around what's going on.
>
> thanks
> > Regards,
> >
> > Kevin Martin
> >
> > On Wed, Aug 9, 2017 at 8:24 PM, bruce  wrote:
> > > hmmmm   update..
> > >
> > > this works...
> > > aa='bash'
> > > echo $aa " pp"
> > > xx= pgrep -f $aa | wc -l
> > > echo $xx
> > >
> > > however, I can't seem to figure out how to enclose the aa var in
> > > single quotes within the pgrep.
> > >
> > > thoughts/comments..
> > >
> > > thanks
> > >
> > > On Wed, Aug 9, 2017 at 8:47 PM, bruce  wrote:
> > > > trying to get the following to output
> > > >   pgrep -f 'bash' | wc -l
> > > >
> > > > the var $xx has the cmd...
> > > >   something's missing to allow the backtics to run the cmd..
> > > >   if the cmd is hadcoded.run, it works..
> > > >
> > > > can't see what the homer simpson "doh" moment is!
> > > >
> > > > thanks
> > > >
> > > > #!/bin/bash
> > > > #
> > > > # ptest.sh
> > > > #
> > > > # use predefined variables to access passed arguments
> > > > #
> > > > # $1
> > > > aa=$1
> > > > aa='bash'
> > > > echo $aa " pp"
> > > > xx="pgrep -f '"${aa}"' | wc -l"
> > > > echo $xx   <<< this dsplays the test pgrep
> > > > echo `$xx`   <<  err msg
> > > > echo `${xx}`  << err msg...
> > > >
> > > > ## trying to get -- pgrep -f 'bash' | wc -l <<
> > > > ## i'm getting a Usage: pgrep [....] err msg..
> > >
> > > users mailing list -- [e-mail]
> > > To unsubscribe send an email to [e-mail]
> >
> > users mailing list -- [e-mail]
> > To unsubscribe send an email to [e-mail]

[Ed Greshko]

On 08/10/2017 10:07 AM, bruce wrote:
> the test was to (1) replicate the results I get from the cmdline.
> and to then (2) be able to pass a input/var to then generate the pgrep
> count results
>
> the initial cmdline pgrep  -- pgrep -f 'bash' | wc -l
>  -- on the test box, this returns a "50" count
>
> in testing using php/bash -- i get a "51"
>
> #!/bin/bash -f
> #
> # ptest.sh
> #
>
> pgrep -f 'bash' | wc -l
>
> on the test centos box, there is no pgrep -c << option.. haven't
> checked the fedora yet

You do realize that when you execute the shell script ptest.sh you create one more
process with "bash" in it?

So....

[egreshko@meimei ~]$ pgrep -f 'bash' | wc -l
4
[egreshko@meimei ~]$ ./pt.sh
5

is totally correct.