identifying what's running ( was Re: [Novalug] "10 Linux commands you've never used" article)

[donjr]

On Thu, 2007-02-22 at 15:18 -0800, Beartooth wrote:
> On Thu, 22 Feb 2007, donjr wrote:
> 
> 
> > Like all shell scripts the first #! must be the first two(2) characters
> > of the file.
> 
>  	Well, I had a blank line at the top. Got rid of it -- and 
> now the complaints are about line 9 ...
> 
> >>  	Now running it gives me a bunch of :
> >>
> >> ../WhatsitDo: line 10: [: missing `]'
> >> ../WhatsitDo: line 10: [: missing `]'
> >> ../WhatsitDo: line 10: [: missing `]'
> >> ../WhatsitDo: line 10: [: missing `]'
> >>
> >>  	Trouble is, I'm unclear whether "line 10" counts the
> >> commented out lines, or the blank line, or both, or neither. And
> >> I don't see a "[" to mate another "]" to.
> >>
> >>  	Here's what I have, if email formatting doesn't mess it
> >> up :
> >>
> >>    GNU nano 1.3.12           File: WhatsitDo
> >>
> >>
> >>   #!/bin/sh
> >>   #
> >>
> >>   LAST=none
> >>   for PREPROCESS in $(ps -e | awk '{print $4}') ; do
> >>     PROCESS=${PREPROCESS//\/0}
> >>     MAN=$(man -f ${PROCESS})
> >>     TEST_MAN=${MAN//nothing appropriate}
> >>     if [ "${#MAN}" = "${#TEST_MAN}" -a "${PROCESS}" != "${LAST}"]
> >> ; then
> >>       LAST=${PROCESS}
> >>       echo ${MAN}
> >>       echo
> >>     fi
> >>   done | less
> >>
> >>  	(In my actual file, the long line has ], then
> >> space-semicolon-space, then the word 'then' with a space after
> >> it -- which is not how it looks above on this end.) Can any of
> >> you tell what I've still got wrong??
> >
> > Then try the following versions (I also made sure that all lines are
> > less then 75 characters, so line wrap shouldn't be a problem either):
> >
> > #!/bin/sh
> > #
> > for PREPROCESS in $(ps -e|awk '{print $4}'|sort -u)
> > do
> >  PROCESS=${PREPROCESS//\/0}
> >  MAN=$(man -f ${PROCESS})
> >  TEST_MAN=${MAN//nothing appropriate}
> >  if [ "${#MAN}" = "${#TEST_MAN}" ]; then
> >    echo ${MAN}
> >    echo
> >  fi
> > done | less
> 
>  	Ver-r-rry innter-r-rressttingg. I c&p'd that into 
> WatsitDo2, then deleted the "> " from the start of each line, 
> saved it, and ran the new version :
> 
> [btth at localhost ~]$ ./WhatsitDo2
> bash: ./WhatsitDo2: Permission denied
> [btth at localhost ~]$

Did you set the execute bit?
Or you can run the command as:
   sh  ./WhatsitDo2

>  	This despite the fact that I *created* the confounded 
> file as btth. So I tried it as root :
> 
> [root at localhost ~]# ./WhatsitDo2
> -bash: ./WhatsitDo2: No such file or directory
> [root at localhost ~]#
> 
>  	Hmmm -- well, obviously (I think), try :
> 
> [root at localhost btth]# cp WhatsitDo2 /root
> [root at localhost btth]#
> 
>  	and try it again. Oddzooks! Ye gods & little fishes!
> 
> [root at localhost ~]# ./WhatsitDo2
> -bash: ./WhatsitDo2: Permission denied
> [root at localhost ~]#
> 
>  	Here I get nervous. I did "chown -R btth:btth /home/btth" 
> on a whole wad of files I had scp'd from another machine 
> recently. So I *think* I do "chown root:root /root" now -- izzat 
> it??

The command you are looking for is 'chmod' as in:
   chmod +x WhatsitDo2

and then it will execute as a command.

> > I used 'sort -u' (or sort --unique) to replace the "${PROCESS}" 
> > != "${LAST}" related parts of the script.
> >
> > Or an even simpler version that doesn't filter out the entries 
> > that man doesn't find anything appropriate for:
> >
> > #!/bin/sh
> > #
> > for PREPROCESS in $(ps -e|awk '{print $4}'|sort -u)
> > do
> >  PROCESS=${PREPROCESS//\/0}
> >  MAN=$(man -f ${PROCESS})
> >  echo ${MAN}
> >  echo
> > done
> 
> [btth at localhost ~]$ nano -w WhatsitDo3
> [btth at localhost ~]$ ./WhatsitDo3
> bash: ./WhatsitDo3: Permission denied
> [btth at localhost ~]$

Try:
  sh ./WhatsitDo3

> > In fact I feel that it is those entries that don't have any 
> > sort of man entry that you should be most interested in finding 
> > out where they came from.
> 
>  	Yes. So do I copy and chown this one (whatever way 
> works), too?

You use 'chmod'  to change the file access permissions. It is the file
access permissions that control if a file is executable or not and a few
other features.

'chown' is for changing who owns of a file.

Or if you just want to execute a temporary script while testing and what
not it's far easier to just do:
   sh ./name_of_script

Which is what really happens behind the screens when you execute a
command at the prompt.

--  
-- 
 Don E. Groves, Jr. 

$ /usr/games/fortune : 
You will be reincarnated as a toad; and you will be much happier.