Fix wildcard sync command if files have special characters

[briceflaceliere]

Problem encountered:
I am using s5cmd to sync several million files, some of which contain special characters (such as \u00a0, quotes, etc.). However, the sprintf("%q") function used in generateCommand modifies these file names, causing the cp command to no longer find the files correctly.

Solution provided:
To resolve this issue, I used the github.com/kballard/go-shellquote library to properly escape URL parameters without converting UTF-8 characters. This process is applied only when necessary, ensuring file names are preserved.

Test changes:
I modified the tests accordingly. However, I am not certain of the potential impact on other parts of the project. I will be able to confirm if this resolves the synchronization issues once the migration of our millions of files is completed.

Related issues:

• invalid argument ERROR when syncing files that have certain characters in filenames #728
• sync command executes erroneous cp commands when local filenames contain certain characters.  #521
• Error: Files not found (u202f) #691

[igungor]

Hey @briceflaceliere, thanks for sending a patch! Appreciated. Using shellquote looks good to me.

Could you add your scenario to cp integration test case to demonstrate the fix please? Thank you.

s5cmd/e2e/cp_test.go

Lines 2142 to 2146 in 12d1038

	0: equals(`cp s3://%v/sub&@$/test+1.txt s3://%v/sub&@$/test+1.txt`, srcbucket, dstbucket),
	1: equals(`cp s3://%v/sub///test&@$:,?;= 4.txt s3://%v/sub///test&@$:,?;= 4.txt`, srcbucket, dstbucket),
	2: equals(`cp s3://%v/sub/this-is-normal-file.txt s3://%v/sub/this-is-normal-file.txt`, srcbucket, dstbucket),
	3: equals(`cp s3://%v/sub:,?/test; =2.txt s3://%v/sub:,?/test; =2.txt`, srcbucket, dstbucket),
	4: equals(`cp s3://%v/test&@$:,?;= 3.txt s3://%v/test&@$:,?;= 3.txt`, srcbucket, dstbucket),