Deleting Lines Containing a Specified String in Different Files

Question

Suppose there are two files in web/ named foo.php and bar.php. The 1st line of foo.php is "sdajgeSTRINGdsad" and the 10th line of bar.php is "gdfhu98324STRING". The task is to first locate these two files, then delete 1st line of foo.php and 10th line of bar.php given that the specified string is "STRING".

Answer 1

sed can do that :

sed -i.bak '/STRING/d' web/*

Answer 2

To find a file containing a string, use grep. If you want to find which files contain STRING in web/ and all subdirectories:

grep -R "STRING" web/

To edit a file and remove lines containing a string, there are many options but here are two common ones. Since you want to operate on entire lines this is really easy :)

First you could use grep with the -v argument to reverse the search and hide the matched lines from the output instead of showing them. For your first file, let's do this using sponge. This will allow us to read your file, filter it, then write it back to the same file all in one motion:

grep -v "sdajgeSTRINGdsad" foo.php | sponge foo.php

For your second example we'll do the same thing with grep, but if you don't have sponge you can write it to a different file, then move that file back to the original name:

grep -v "gdfhu98324STRING" bar.php  > bar.php.cleaned
mv bar.php{.cleaned,}

The second way would be to use sed with the d line delete command. For your first example we will use the in-place file edit with the option to create a .bk backup file:

sed -i.bk '/sdajgeSTRINGdsad/d'  foo.php

Pretty much the same thing could be accomplished by copying the file yourself then using sed to filter the backup and over-write the original:

cp bar.php bar.php.bk
sed '/gdfhu98324STRING/d' bar.php.bk > bar.php

Now to combine these two tasks! Let's make a function so you can do this repeatedly with different strings:

function nuke_string () {
    string="$1"
    path="$2"
    grep -R -l "$string" "$path" | while IFS= read -r file; do
        sed -i.bk "/$string/d" "$file"
    done
}

Once you create that function, you could use it like this:

nuke_string "STRING" web/

Any files containing STRING in web/ would then have those lines removed and a backup copy would be made of the original version. You can create a function like this in your current shell or you can write it to your .bashrc file and have it always available.

Answer 3

There are two alternatives:

1. use find to recursively locate your files (e.g. *.php files) and perl or GNU flavor of sed (both have the -i option) for performing the deletion.

2. What you are asking for looks like a refactoring operation: change the name of an element of code everywhere in the codebase. If my guess is correct, you should check IDEs able to handle php development.

Answer 4

Just make use of grep -l together with -R! Here's a complete one-liner:

grep -Rl "STRING" web/ | xargs sed -i "/STRING/d"