How to replace part of string?

Shell Programming and Scripting
1

Hi Gurus,

I need to replace part of string in file, the string format is below: I can use ABCD to find string, then replace values after "=" sign

ABCD_XXX=value
ABCD_YYY=value

after replace

ABCD_XXX=new_value
ABCD_YYY=new_value

my OS is SunOS 5.10 Generic_150400-64 sun4v sparc sun4v

thanks in advance

2

Hi, you can use an input file with the new key value pairs

$> cat file1
ABCD_XXX=new_value1
ABCD_YYY=new_value2
$> cat file2
foo
ABCD_XXX=value1
ABCD_YYY=value2
bar=baz

Try:

awk 'NR==FNR{A[$1]=$2; next} $1 in A{$2=A[$1]}1' FS='=' OFS='=' file1 file2

Output:

foo
ABCD_XXX=new_value1
ABCD_YYY=new_value2
bar=baz
3

thanks Scrutinizer. Sorry, I didn't give the sample properly. actually, there is only one value for all lines after equal. I updated my initial query. I tried to use awk command, I can use below command to print out correct result, but not sure how to replace it in file.

awk -F"=" '/ABCD/ {print $1"=value"}'  file
4

You can redirect the output to a new file. If ok you can replace the old file with the new file:

nawk -F"=" '/ABCD/ {print $1"=value"}'  file > newfile
1 Like
5

thanks Scrutinizer.

in the file, it has other contents which need to keep "as is". above command only print the match ones. how can I keep these file content as is.
for example:
old file:

aaaaaa
bbbbb
ABCD_XXX=value
ccccc

after replace:

aaaaaa
bbbbb
ABCD_XXX=new_value
ccccc
6

Hi Gurus,
I am able to use below command to get expected result. one more question:
I need to pass variable to this command, somehow it doesn't work.

awk -F"=" '!/ABCD/ {print $0}; /ABCD/ {print $1"=NEW_VALUE"}'  file > new_file

I use below command, it throw out error.

awk -F"=" -v var="$new_value" '!/ABCD/ {print $0}; /ABCD/ {print $1"=${var}"}'  file > new_file
7

simplified and fixed:

awk -F= -v var="$new_value" '/ABCD/ {$1= "=" var} 1' file > new_file
2 Likes
8

Not quite there $1 contains the variable name and is overwritten with "=" newvalue, try:

awk -F= -v var="$new_value" '/ABCD/ {$2 = var} 1' OFS== file > new_file
1 Like
9

ti works. thanks.

10

Thanks.