Find lines in multiple files starting with text, and replacing with lowercase-CodePudding

I'm trying to find all files that contains lines that start with a specific string, and then set everything in that line after that to lowercase. I'm able to do parts of what I want but can't seem to figure out how to get it all to work.

Here's an example of the string I'm looking for:

      _assetBundleName: SomeDirectory/ChildDirectory

and I need it to be:

      _assetBundleName: somedirectory/childdirectory

So I can't convert the entire line to lower case, just everything after the string I'm looking for (which is _assetBundleName: ). And I need to perform this on many files (all directories and subdirectories from where the command is run).

sed 's/[a-z]/\L&/g' converts everything to lowercase, not just everything after the string I've found.

CodePudding user response：

You can use this gnu-sed with 2 capture groups:

sed -E 's/(_assetBundleName:)(.*)/\1\L\2/' file

\L\2 will lowercase only the 2nd capture group content.

As noted above that this requires gnu-sed. If you don't have that then you can use this awk command:

awk 'BEGIN {FS=OFS=":"} 
$1 ~ /_assetBundleName/ {$2 = tolower($2)} 1' file

CodePudding user response：

Using sed

$ sed '/_assetBundleName:/s/:.*/\L&/' input_file

$ sed "/_assetBundleName:/s/\(.*\)\(:.*\)/echo '\1'\$(echo \\2 | tr 'A-Z' 'a-z')/" file | bash

Output

 _assetBundleName: somedirectory/childdirectory

CodePudding user response：

A Perl solution:

perl -i -pe 's{(_assetBundleName:)(.*)}{$1\L$2}' file1 file2 ...

The Perl one-liner uses these command line flags:
-e : Tells Perl to look for code in-line, instead of in a file.
-p : Loop over the input one line at a time, assigning it to $_ by default. Add print $_ after each loop iteration.
-i : Edit input files in-place (overwrite the input file).
-i.bak : Edit input files in-place (overwrite the input file). Before overwriting, save a backup copy of the original file by appending to its name the extension .bak.

s{PATTERN}{REPLACEMENT} : replace PATTERN with REPLACEMENT.
.* : any character, repeated 0 or more times.
$1, $2: first and second capture groups, captured with parentheses.
\L$2 : lowercase everything in the second capture group.