Compare files and extract matches on linux

Essentially, we understand that what the questioner wants to do is to extract the commonality between the list of filenames written in the file (not including the directory portion) and the filenames of the files actually contained in a particular directory.

In implementing this, @nekketsuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuSpecifically,

• File name does not contain line breaks

I believe that is necessary.

On the other hand, if this has been achieved, I think we can use grep-Fxf, which is an idiom for calculating the common part of a row in the unix system.specifically:

 (cd/usr/local/actualfilesdir/&ls-1) | grep-Fxf filename.txt

The above provides a list of common file names, so if necessary, we can do various things by turning the for statement.

If I were myself,

• The filename does not contain a new line.
• The filename does not contain a double quotation.
• filenames.txt has fewer files than actualfilesdir has.

If this is the case, the shell script continues to follow as follows:

# For example, if you want to echo the extracted filename,
cat filenames.txt | xargs-I{}sh-c' [-e"/usr/local/actualfilesdir/{}]&echo{}'

However, if the follow-up processing is complicated, write the program in a different programming language instead of a shell script.This is because I find it difficult to maintain complicated actions in the shell script.

Whether it's efficient or not, separate explanation:

${cat filename.txt;ls/usr/local/actualfilesdir;}|sort|uniq-d

That 2 (other than No such file or directory of ls is hidden):

$(cd/usr/local/actualfilesdir&xargsls-12>/dev/null)<filenames.txt

Prerequisites:

• The filename does not contain a new line.
• filenames.txt does not contain duplicate names.

Is this the image?

$pwd
/tmp/work

$ ll
total 28K
-rw-rw-r -- 1 genzouw wheel 29 1908:48 1.txt
-rw-rw-r -- 1 genzouw wheel 29 1908:482.txt
-rw-rw-r -- 1 genzouw wheel 29 1908:483.txt
-rw-rw-r -- 1 genzouw wheel 29 1908:484.txt
-rw-rw-r -- 1 genzouw wheel 29 1908:485.txt
-rw-rw-r -- 1 genzouw wheel 59 1908:5011.txt
-rw-rw-r -- 1 genzouw wheel 189 1908:48 list.txt

$ catlist.txt
1.txt
3.txt
5.txt

$ ls/tmp/work | grep-w-f list.txt
1.txt
3.txt
5.txt