How to replace a whole line with sed?
RegexSedRegex Problem Overview
Suppose I have a file with lines
aaa=bbb
Now I would like to replace them with:
aaa=xxx
I can do that as follows:
sed "s/aaa=bbb/aaa=xxx/g"
Now I have a file with a few lines as follows:
aaa=bbb aaa=ccc aaa=ddd aaa=[something else]
How can I replace all this lines aaa=[something] with aaa=xxx using sed?
Regex Solutions
Solution 1 - Regex
Try this:
sed "s/aaa=.*/aaa=xxx/g"
Solution 2 - Regex
You can also use sed's change line to accomplish this:
sed -i "/aaa=/c\aaa=xxx" your_file_here
This will go through and find any lines that pass the aaa= test, which means that the line contains the letters aaa=. Then it replaces the entire line with aaa=xxx. You can add a ^ at the beginning of the test to make sure you only get the lines that start with aaa= but that's up to you.
Solution 3 - Regex
Like this:
sed 's/aaa=.*/aaa=xxx/'
If you want to guarantee that the aaa= is at the start of the line, make it:
sed 's/^aaa=.*/aaa=xxx/'
Solution 4 - Regex
sed -i.bak 's/\(aaa=\).*/\1"xxx"/g' your_file
Solution 5 - Regex
If you would like to use awk then this would work too
awk -F= '{$2="xxx";print}' OFS="\=" filename
Solution 6 - Regex
This might work for you:
cat <<! | sed '/aaa=\(bbb\|ccc\|ddd\)/!s/\(aaa=\).*/\1xxx/'
> aaa=bbb
> aaa=ccc
> aaa=ddd
> aaa=[something else]
!
aaa=bbb
aaa=ccc
aaa=ddd
aaa=xxx