Question

I have a big home directory, under which there are many jar files. I need to aggregate the contents of all txt files, within the jar files in my home directory, into a single text file.

Can someone help me with this? I don’t know how to write a script for this. I am using a Linux system.

To recap, I need to:

1. Find all jar files
2. Find all txt files within the jar files
3. Get the contents of these txt files into a single output file

Answer 1

If we omit proper whitespace handling in file names, it boils down to:

searchdir='/home/username/'
outputtxt='/home/username/out.txt'

for jar in $(find "$searchdir" -iname '*.jar'); do
  for txt in $(unzip -l "$jar" | awk '/\.txt$/ {print $NF}'); do
    unzip -c "$jar" "$txt" | tail -n +3 >> "$outputtxt"
  done
done

You can also omit | tail -n +3 from the inner most loop if you wish to include the unzip header in the output file. An example header:

Archive:  /home/username/filename.jar
  inflating: META-INF/maven/pom.xml