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Using SED to generate new file from template

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# 1  
Old 07-25-2009
Using SED to generate new file from template

Hi there!

I am using a BASH script to read a CSV file (containing variable values)using while read, and for every record I want SED to get a template from a file, and using the variables read from the CSV, write a new file.

current_ifs=$IFS ; #backup original IFS, need "," for thw CSV file
while read VAR1 VAR2 VAR3 FILENAME; do
 sed -n -e 's/VAR1/$VAR1/g'\
 -e 's/VAR2/$VAR2/g'\
 -e 's/VAR3/$VAR3/g'\
done < $CSV
IFS=$current_ifs; #redefines original IFS

But it looks like I am missing something. TEMPLATE is on the same folder, new file can go to any folder (would be nice to set it)

Help anyone?
# 2  
Old 07-26-2009
Just the code is not enough.
Give a listing of the contents of all the files involved.
What is this TEMPLATE thing?
What is the "w" in TEMPLATE w $FILENAME?
What should the output look like?
In this forum,if you dont get a response in 1 or 2 hours, then most probably, your question is not clear.
# 3  
Old 07-26-2009
I've read somewhere about this "w" option on writing the output to a different file than input, but I guess I read it wrong or not sure how to use it...

Anyway, I went back to redirect using > and it worked!

Just for the record... the template files are templates with placeholder for Cisco router config files, like:

!configlet for HNAME (IP_ADD)
conf t
interface INT
 ip address IP_ADD mask MASK

And the source CSV file contains the hostname, interface number, IP addresses and subnet masks for each of the 1000+ devices I needed to create a configuration file... Smilie CSV also had the device type for each device (using the same types as TEMPLATE) and a FILENAM for each device so the script would write a different file for each device.

As I had many different templates, I also improved the code to save them on different folders according to the type.

I'll post latter the final script Smilie

Thank you for your reply!
# 4  
Old 07-26-2009
Yes, you are right, with the "w" you can write the output to a file.
but the syntax should be as follows:

Where "TEMPLATE" will be the outputfile.

Did yo realize that you have used the FILENAME variable at both, the "read" as well as the input file name?
# 5  
Old 07-26-2009
@ ppucci
Why you don't post a sample input and a sample of required output.
# 6  
Old 07-27-2009
Originally Posted by edidataguy
Yes, you are right, with the "w" you can write the output to a file.
but the syntax should be as follows:

Where "TEMPLATE" will be the outputfile.

Did yo realize that you have used the FILENAME variable at both, the "read" as well as the input file name?
Well... guess I'll try "w" next time now I know how it works Smilie... does it have any difference to > after all?

As for the FILENAME var... I actually read it from the CSV archive (it is one of the columns) and then I apply it as the name of the output file (that's what I did on my finished script... but right, at my first example it was (wrongly) on the input file). That "while read" now reads:

while read VAR1 VAR2 VAR3 FILENAME; do
 sed -n -e "s/VAR1/$VAR1/g"\
 -e "s/VAR2/$VAR2/g"\
 -e "s/VAR3/$VAR3/g"\
done < $CSV

Again, this is just an example on who it looks now... I'll post the actual script later Smilie

---------- Post updated 07-27-09 at 01:10 PM ---------- Previous update was 07-26-09 at 02:08 PM ----------

One last thing...

one of the columns on the csv file has values with spaces on it (i.e: interface name) but sed brings that around quotes (i.e: "interface name") and in some cases, it brings in quotes and adds a string to the end (i.e: "interface name"ESS).

What gives? Is there a way to tell sed not to do that?

By the way.... as promissed, here is the script that is working now:

current_ifs=$IFS; #backup original IFS
echo "reading $1"
# while and sed are broken down for readability
 sed -e "s|HNAME|$HNAME|g"\
 -e "s|REGION|$REGION|g"\
 -e "s|SITE_ID|$SITE_ID|g"\
 -e "s|IP_MGMT|$IP_MGMT|g"\
 -e "s|NEW_MASK|$NEW_MASK|g"\
 -e "s|ROU_1_IP|$ROU_1_IP|g"\
 -e "s|ROU_2_IP|$ROU_2_IP|g"\
 -e "s|DIST_SW2_IP|$DIST_SW2_IP|g"\
 -e "s|HSRP|$HSRP|g"\
done < $1
IFS=$current_ifs; #redefines original IFS

Last edited by ppucci; 07-27-2009 at 09:20 PM..
# 7  
Old 07-28-2009
Double check your code.
Why are these lines repeated in your code? Intentionally done?

I would sugest changing all the lines as follows:

Why do you need the "-e" and the "/g" options.

Regarding the " " issue post the input and the output.

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