Script: SED for Copy/Paste Lines from Files

unihiekka · 10-07-2008, 05:05 AM

I have two files, say, one.dat and two.dat. I want sed to find the line

Code:

extern MY_FLOAT ...;

in one.dat and then copy the "MY_FLOAT ...;" (without the quotes, of course) to two.dat exactly on the line before

Code:

int main(

. The ellipsis ... indicates a sequence of variables (e.g. a,b,c,d --- which varies from one one.dat file to another). The line with extern MY_FLOAT is always closed by a semicolon and the so should the pasted counterpart in two.dat.

I know it's possible but sed is complex and I know only the very basics.

Thanks!

colucix · 10-07-2008, 05:42 AM

An hybrid solution using sed and grep:

Code:

sed "/int main[(]/ i/$(grep ^extern\ MY_FLOAT one.dat)" two.dat

this insert the line matching "extern MY_FLOAT" in one.dat, above the line matching "int main(" in two.dat. Surely there is a better way to do.

unihiekka · 10-07-2008, 06:12 AM

And then another line for sed to remove the "extern" from the pasted line in two.dat:

Code:

sed 's/extern\ MY_FLOAT/MY_FLOAT/' two.dat

Works perfectly, thanks! Only one change should be made:

Code:

sed "/int main[(]/ i $(grep ^extern\ MY_FLOAT one.dat)" two.dat

without the forward slash after i (otherwise the forward slash is used as pasted text).