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Redis – How to use sed to replace multiple lines

What would be the right syntax to perform an inplace update to a file from:

"redis"=>array(
    'enabled' => false,

to

"redis"=>array(
    'enabled' => true,

I’ve tried things like but it’s not working

sed -i "s/"redis"=>array(n    'enabled' => false/"redis"=>array(n    'enabled' => true/" input.php
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4

Answers


  1. 0

    You can use

    sed -i '/"redis"=>array($/{N;s/('"'"'enabled'"'"' => )false/1true/}' file

    See the online demo:

    #!/bin/bash
s='"redis"=>array(
    '"'"'enabled'"'"' => false,'
sed '/"redis"=>array($/{N;s/('"'"'enabled'"'"' => )false/1true/}' <<< "$s"

    Output:

    "redis"=>array(
    'enabled' => true,

    Here,

    • /"redis"=>array($/ – match a line that ends with "redis"=>array( string and
    • {N;s/('"'"'enabled'"'"' => )false/1true/} – N appends a newline char and adds the next line to the pattern space, and s/('enabled' => )false/1true/ matches and captures into Group 1 'enabled' => substring and then just matches false and the 1true replaces the match with the Group 1 value + true substring.
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  2. 0

    If you have gnu sed then your attempted approach will fine with -z option:

    sed -i -Ez "s/("redis"=>array(n[[:blank:]]*'enabled' => )false/1true/" file

cat file

"redis"=>array(
    'enabled' => true,

    Explanation:

    • -z: separate lines by NUL character
    • -E: Enable extended regex mode
    • ("redis"=>array(n[[:blank:]]*'enabled' => )false: Match "redis"=>array( line followed by line break and 'enabled' => part in capture group #1, followed by false.
    • 1true: puts captured value from group #1 followed by true
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  3. 0

    With perl:

    perl -0777 -ne '$#ARGV==1 ? $s=$_ : $#ARGV==0 ? $r=$_ :
                print s/Q$s/$r/gr' search.txt replace.txt ip.txt
    • search.txt file containing content to be searched
    • replace.txt file containing content to be used for replacement
    • ip.txt file on which the substitution has to be performed
    • -0777 slurp entire file contents as a single string, so this solution isn’t suitable if input file is too large to fit memory requirements
    • $#ARGV is used to know which file is being read
    • $s saves the search text, $r saves the replacement text
    • s/Q$s/$r/gr here, Q is used to match search text literally
    • Use perl -i -0777 ... for in-place modification.

    See my blog post for more examples and alternatives.

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  4. 0

    This might work for you (GNU sed):

    sed '/"redis"=>array($/!b;n;/^s*'''enabled''' => false,/s/false/true/' file

    Look for a line that ends "redis"=>array(, print it and fetch the next line.

    If that line contains 'enabled' => false, replace false by true.

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