Bash substitution; remove everything after the string

Answer 1

Try:

sed -i 's/^DATE:.*$/DATE: XXXX/g' filename

Answer to your 2nd question depends on how often you need to write such things. If it's a one time thing and time is limited it's better to ask here. If not, it's better to learn how to do it by using an online tutorial.

Answer 2

You can use the following code also

> var="DATE: 12 jan 2009, weather 20ºC" 
 > echo $var | sed -r 's!^(DATE:).*$!\1 XXXX!'

Answer 3

You can use the shell

while IFS=":" read -r a b
do
  case "$a" in
   DATE* ) echo "$a:XXXX";;
   *) echo "$a$b" ;;
  esac
done < "file"

or awk

$ cat file
some line
DATE: 12 jan 2009, weather 20ºC
some line

$ awk -F":" '$1~/^DATE/{$2="XXXX"}1' OFS=":" file
some line
DATE:XXXX
some line

Answer 4

If your line isn't in a file, you can do it without sed :

var="DATE: 12 jan 2009, weather 20ºC"
echo "${var/DATE:*/DATE:xxxxx}"

Answer 5

while read line
do
    echo "${line/#DATE*/DATE:xxxxx}"
done < myfile