Appending # to the start of specific line in a properties file

UNIX for Advanced & Expert Users
1

Hi,
I have the following file,

ABC.txt:

ABC=123
DEF=234
FGH=345

Based on my validation and conditional processing it is observed that i need to comment or append # before DEF=234

so the same file ABC.txt should look as follows

ABC=123
#DEF=234
FGH=345

Sorry if its a repost/wrong section... this is my first post.
Please help me out here...

Thanks in advance,
Mihir

2

Everything is fine, just use code tags when you post code, data or logs etc. thanks :slight_smile:

If "DEF=234" is the only identifier to match, you can try:

sed 's/^DEF=234/#&/' infile
3

I dont want starts with, i want it to be something like,
I want to search 234 value and append # to the same line which contains the string 234

for instance

ABC=123
DEF=234
EFG=2356
DFGT=234

should be updated to

ABC=123
#DEF=234
EFG=2356
#DFGT=234

Can you help me out on this?

Sorry for the confusion earlier... It seems i failed to phrase the proper query.

4 
$ nawk '{if ($0~/234/) {print "#"$0}else {print $0}}' infile
5

No worries, I think I missed that point^^

sed 's/.*234.*/#&/' infile
ABC=123
#DEF=234
EFG=2356
#DFGT=234

Edit:
And the awk line a tad shorter:

awk '/234/ {print "#"$0; next}1' infile
6 
 
$ perl -lane 'if($_ =~ /234/){print "#$_";}else{print $_}' test
ABC=123
#DEF=234
EFG=2356
#DFGT=234
7 
sed '/234/s/^/#/' infile

awk '/234/{$0="#"$0}1' infile