How do I parse the output of a command that output to standard out?

gauol · 01-07-2008, 12:59 PM

I am currently trying to take the output, written to standard out, of one of our programs and reformat it in a way that is more useful to those in my group. It has proven difficult to get the actual program re-written (the usual delays) so I believe I should able to accomplish this via a shell script. The one restriction I have is that this will using Busy Box with a limited toolset.

Anyway the real point of this question is figure out… When doing this type of parsing via a shell script do I need to send the output to a file a then parse that or can I parse it directly from standard out?

I have a background in programming but haven’t used in some time so its time get into it. I see this as a both easy (the hard work is done via the program) and hard (I will have to do conditional testing to more the data correctly).

Many Thanks (if you need more info, I'm sure you will, just let me know)

Poetics · 01-07-2008, 01:04 PM

You can merely pipe the output to a new command (awk or sed, for instance), or you can wrap the entire script process within another script (such as a perl script that can parse the output using backticks).

gnashley · 01-07-2008, 02:01 PM

For very short output you can just use something like this:
VALUE="$(your_command)"
For mulitple lines you'll find it easier to use a pipe or redirect the output to a file for further processing. Sometimes it's useful to use the 'tee' program for this, if you want to see the output as well as put it in a file.

gauol · 01-15-2008, 09:28 AM

I think I could use an assist, its been so long since I tried any of this, the output of the program looks like this

devid=0x5a2f
swtguud=4446k10800418brr
chiswt 24 "4446k10800418brr" # "swt90is24rs-m Vold" vmaliid 1

devid=0x5a2f
swtguud=4446k10800418brr
chiswt 24 "4446k10800418brr" # "swt90is24rs-m Vold" vmaliid 1

it can get much larger depending on the number of nodes. What like to do is send all this output to a file in the format of just one line.

devid=0x5a2f,swtguud=4446k10800418brr,chiswt 24 "4446k10800418brr",# "swt90is24rs-m Vold" vmaliid 1

How might I go about this?

I see this as the first step and afterwards I will parse this file for the output I need

gauol · 01-15-2008, 09:29 AM

ps thanks for all the help so far and future

theNbomr · 01-15-2008, 10:00 AM

Assuming that your data records are separated by double newlines as you showed, this should work:

Code:

yourProgram | perl -e '$/ = "\n\n"; while( <> ){ @rec=split /\n/, $_; print join(",", @rec), "\n"; }'

--- rod.

ghostdog74 · 01-15-2008, 10:26 AM

GNUawk

Code:

# awk 'BEGIN{RS="";OFS=","} {$1=$1}1' file
devid=0x5a2f,swtguud=4446k10800418brr,chiswt,24,"4446k10800418brr",#,"swt90is24rs-m,Vold",vmaliid,1
devid=0x5a2f,swtguud=4446k10800418brr,chiswt,24,"4446k10800418brr",#,"swt90is24rs-m,Vold",vmaliid,1

gauol · 01-15-2008, 10:43 AM

theNbomr
Unfortunately perl is not available on this system thanks though

ghostdog74
worked beautifully but I forgot that the output changes so i will have to re think this. Many thanks!

PAix · 01-15-2008, 11:15 AM

OK, so an oversight isn't exactly the end of the world.

If you share your output, trying to make sure that it's truely representative of your file, then we can have a bit of a think about it while you are doing the same. That way if you come up empty or with a less than optimal solution then there might be a ready solution to your problem all thought out ahead of time.

gauol · 01-17-2008, 01:54 PM

well after toying around the the system i found that the sys already has a cvs file with this info in it so there is no need for me to reinvent the wheel. Now have to develop a script to parse this file. Thanks for the help and I sure I'll be back when I dig into that.