Hi all! I'm very new in bash and right now I can't find a way to solve my problem. I hope somebody can help.

Right now I have an array:

array_of_channels=( channel1 channel2 channel3 )

and a "new_main.cpp" file where I want to append new lines after the ones containig the elements of the array_of_channels. For example the original "main.cpp" contains:

(text...)

sc_fifo<double> channel1("channel");
sc_fifo<double> channel2("channel");
sc_fifo<double> channel3("channel");

(text...)

And I want to have in the "new_main.cpp" file:

(text...)

sc_fifo<double> channel1("channel");
#ifdef COVG
p[1] = "f channel1";
#endif

sc_fifo<double> channel2("channel");
#ifdef COVG
p[2] = "f channel2";
#endif

sc_fifo<double> channel3("channel");
#ifdef COVG
p[3] = "f channel3";
#endif

(text...)


So I wrote:

channel_index=1

for s in ${array_of_channels[*]}; do

sed '/[^ ]*sc_fifo[^ ]*<[a-z]*> '$s'[\(].*;/ a\#ifdef COVG\np[i] = "f '"$s"'";\n#endif\n' <main.cpp >new_main.cpp

let "channel_index++"
done

The result is that, for every loop, the sed command is writing over the whole file, so everything I get in the "new_main.cpp" is:

(text...)

sc_fifo<double> channel1("channel");
sc_fifo<double> channel2("channel");
sc_fifo<double> channel3("channel");
#ifdef COVG
p[3] = "f channel3";
#endif

(text...)

Would somebody know how to solve it?

The issue is you are reading from main.cpp and writing to new_main.cpp. main.cpp never gets updated with the change you made in any of the previous iterations of the loop, and only the last iteration makes it through. There are a couple of ways to solve this:

1. after the sed command do a : mv new_main.cpp main.cpp -- to overwrite the main.cpp
2. use sed -i ;
a. remove the less-than sign from '< main.cpp' and just leave 'main.cpp' -- sed can read the file directly without redirection.
b. remove the > new_main.cpp part completely.

Remember to make a backup of main.cpp before you run the script.

Also, please only post your question in one forum at a time. Thanks.

Hi rn. Thanks a lot for your answer! Both options work perfectly.

Ah.. sorry for posting twice.. from now own I'll add the post to just one topic.