replacing just one specific occurance in file

[Bill McNAMARA_1]

If following is my file,
how do I replace just the first LPC=10 to LPC=40
and not the second or further occurances?

Thanks,
Bill!

[ Isup_SS7_Platform ]
LPC=10, classname=SS7_Stack_1, MtpProtocol=ITU, IsupProtocol=ITU

[Isup_Dpc_10_20]
LPC=10
DPC=20
~
~
~

[Bill McNAMARA_1]

The 40 can come from
a: specific change
b: adding 30

It's possibly better to just change to
LPC=101
by adding a 1 to the end of what's in the file originally and the format can be different.. ie not always a decimal number.

Thanks,
Bill

[Steven Sim Kok Leong]

Hi Bill,

# cat file | sed -e 's/LPC=10,/LPC=40,/'

I know I am cheating but hey, it works :P

Hope this helps. Regards.

Steven Sim Kok Leong

[Steven Sim Kok Leong]

Hi Bill,

Forgot to add, try using the comma (,) to advantage.

Hope this helps. Regards.

Steven Sim Kok Leong

[Bill McNAMARA_1]

That changes the second occurance also.. I though it did that just with the g ..?

/usr/bin/sed -e "s|^$key=$LPC|$key=$value|" $filename > $TMP_WORKFILE

where key=LPC
LPC=10
value=${LPC}1

Later,
Bill

[Robin Wakefield · Accepted solution]

Hi Bill,

Try:

/usr/bin/sed -e "1,/$LPC/s|^$key=$LPC|$key=$value|" $filename > $TMP_WORKFILE

This will stop replacing once it's found the 1st occurrence.

The g switch is for replacing all occurrences in *each* line.

Rgds, Robin.

[Bill McNAMARA_1]

thats for clearing that up Robin!

(Back into a scripting week, hope the forums stay online!)

Later,
Bill

[Steven Sim Kok Leong]

Hi Bill,

Using the sample you provided, only the first occurrence of LPC=10 has a comma after it. Thus, using the comma will work for your sample above.

However from your response, I gather that the second occurrence of LPC=10 in your full text actually has a comma tagging after it. If that is the case, then using the comma to differentiate the first occurrence from the rest in my method will not work.

Hope this helps. Regards.

Steven Sim Kok Leong

[Bill McNAMARA_1]

Right on Steven,

That works fine too.

Later,
Bill