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Linux / Unix: Sed Substitute Multiple Patterns [ Find & Replace ]

I‘m using the date +’%D_%T’ to store Unix system date and time in a shell variable called $_now:

_now=”$(date +’%D_%T’)”
echo $_now


I’d like to replace / and : with _. I’m aware of the following sed command:

sed ‘s/\//_/g
> s/:/_/g’ <<<"$_now"


How do I specify two pattern within the same sed command to replace | and : with _ so that I can get output as 01_20_12_16_10_42?

You can use any one of the following sed substitute find and replace multiple patterns:

sed -e 's/Find/Replace/g' -e 's/Find/Replace/g' <<<"$var"
sed -e 's/Find/Replace/g' -e 's/Find/Replace/g' < inputFile > outputFile
out=$(sed -e 's/Find/Replace/g' -e 's/Find/Replace/g' <<<"$var")


sed 's/Find/Replace/g;s/Find/Replace/g' <<<"$var"
sed -e 's/Find/Replace/g;s/Find/Replace/g' <<<"$var"
sed -e 's/Find/Replace/g;s/Find/Replace/g' < inputFile > outputFile
out=$(sed -e 's/Find/Replace/g;s/Find/Replace/g' <<<"$var")

Examples: Find And Replace Sed Substitute Using a Singe Command Line

_now="$(sed -e 's/\//_/g;s/:/_/g' <<<$(date +'%D_%T'))"
echo $_now

Sample outputs:


Here is another version:

_now=$(sed 's/[\/:]/_/g' <<<$(date +'%D_%T'))
echo "$_now"

Sample outputs:

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{ 5 comments… add one }
  • sylvainulg January 23, 2012, 10:10 am

    Alternatively, one could tell `date` the desired format, like date +%Y-%m-%d-%H-%M

  • LOL LOLSKI December 21, 2012, 4:11 pm

    Just do:

    now=`date +”%m_%d_%y_%H_%M_%S”`
    echo $now

  • gabriel April 1, 2013, 3:52 pm

    Man was showing sed not date command…

  • Panna November 25, 2014, 4:04 pm

    I have a not well experience with awk and sed. if any find the solution?
    I have a two variable like..
    a-fdfgh3 ##here two word in one column and may you can say in row
    $var2=a-45afd4 string1 string2 string3 string4
    a-fdfgh3 string1 string2 string3 string4
    a-hfdj3e string1 string2 string3 string4
    a-jkkl3l string1 string2 string3 string4

    i want to find $var1 data in $var2 and the output should be
    Example: a-45afd4 string1 string2 string3 string4
    a-fdfgh3 string1 string2 string3 string4

    ##rest all column row should not come

  • SANDY March 9, 2016, 3:50 pm

    What is the output of “date -u +%V`uname`|sha512sum|sed ‘s/\W//g'”?

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