how to edit multiple lines using script

Question

I have a config file that looking like this

"gpu_thread_num" : 6,

"gpu_threads_conf" : [ 
    { "index" : 0, "intensity" : 1000, "worksize" : 8, "affine_to_cpu" : false },
    { "index" : 1, "intensity" : 1000, "worksize" : 8, "affine_to_cpu" : false },
    { "index" : 2, "intensity" : 1000, "worksize" : 8, "affine_to_cpu" : false },
    { "index" : 3, "intensity" : 1000, "worksize" : 8, "affine_to_cpu" : false },
    { "index" : 4, "intensity" : 1000, "worksize" : 8, "affine_to_cpu" : false },
    { "index" : 5, "intensity" : 1000, "worksize" : 8, "affine_to_cpu" : false },
],

The number of lines in "gpu_threads_conf" always must be equal to "gpu_thread_num" and this num changing from time to time depend on number of GPU's connected. I have a start.sh script that checks this number and change "gpu_thread_num" with sed, but i can't figure out how to change "gpu_threads_conf".

I lost my hope trying to figure out how to do it myself and really need your help.

Instead of modifying the file, why not recreate it each time? — Ignacio Vazquez-Abrams
– Ignacio Vazquez-Abrams, Commented Aug 25, 2017 at 22:58
@IgnacioVazquez-Abrams it's too large and contains more complex stuff. — kusayu
– kusayu, Commented Aug 25, 2017 at 23:03
@Barmar, unfortunately, it's only looking like json, but it is not. — kusayu
– kusayu, Commented Aug 25, 2017 at 23:24
Yeah, just noticed the comma after the last element of the array. That's allowed by Javascript, but not JSON. — Barmar
– Barmar, Commented Aug 25, 2017 at 23:25

Totoc1001 · Accepted Answer · 2017-08-26 00:20:16Z

1

If you want to update the number of "gpu_thread_num" according to the number of lines, you can use the following script:

#!/bin/sh

#Take the first line
idx=$(grep -n gpu_threads_conf "$1")
#line after gpu_thread...
START=$(($(echo "$idx" | sed "s|:.*||")))

idx2=$(grep -n "]," "$1") 
END=$(($(echo "$idx2" | sed "s|:.*||") - 1))

#Returns 3
echo $START

#returns 9
echo $END

#returns 6
RESULT=$(($END - $START)) 

#substitute the  number in the file
sed -i "s|\"gpu_thread_num\" :.*|\"gpu_thread_num\" : $RESULT,|" $1

it will update directly your config file...

sh Test.sh MyConf.cfg

I hope with one or other solution, you'll find your happiness :)

answered Aug 26, 2017 at 0:20

Totoc1001

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1 Comment

kusayu Over a year ago

This is a perfect solution and it so beautiful that i can't stop to run it back and forth, lol. That's why i was so slow to accept and upvote it. Thank you very much, you're awesome!

Totoc1001 · Accepted Answer · 2017-08-26 00:17:35Z

0

I'm not sure to have understood well, but you can try something like this:

#!/bin/sh


echo "\"gpu_threads_conf\" : [ " > TOTO.txt
END=6
for i in $(seq 2 $END); do
    echo "$i"
    echo     "{ \"index\" : $i, \"intensity\" : 1000, \"worksize\" : 8, \"affine_to_cpu\" : false }," >> TOTO.txt
done
echo "]," >> TOTO.txt

Result:

$ cat TOTO.txt
"gpu_threads_conf" : [
{ index : 1, intensity : 1000, worksize : 8, affine_to_cpu : false },
{ index : 2, intensity : 1000, worksize : 8, affine_to_cpu : false },
{ index : 3, intensity : 1000, worksize : 8, affine_to_cpu : false },
{ index : 4, intensity : 1000, worksize : 8, affine_to_cpu : false },
{ index : 5, intensity : 1000, worksize : 8, affine_to_cpu : false },
{ index : 6, intensity : 1000, worksize : 8, affine_to_cpu : false },
],

Just use END with the number of "gpu_thread_num" and I guess that's it.

I hope I understood well the question.

Regards Thomas

edited Aug 26, 2017 at 0:17

answered Aug 25, 2017 at 23:34

Totoc1001

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2 Comments

kusayu Over a year ago

For some reason it's not working for me. kusayu@laptop:~/oc_nv.sh$ ./foo.sh ./foo.sh: 5: ./foo.sh: Syntax error: Bad for loop variable

kusayu Over a year ago

it works with /bin/bash instead of sh. Now i can just delete "gpu_threads_conf" every time from the config file and put it back using the code from your answer. Thank you very much.

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