Question

I’ve found many examples on how to search for files that exist in a jar, but I want to find text that exists in a file that exists in a jar. How can I do this without unpacking all of my jar files?

#!/bin/sh

LOOK_FOR="string to find inside a file inside a jar"

for i in `find . -name "*jar"`
do
  echo "Looking in $i ..."
  jar tvf $i | grep $LOOK_FOR > /dev/null
  if [ $? == 0 ]
  then
    echo "==> Found \"$LOOK_FOR\" in $i"
  fi
done

Answer 1

If you just want to see if any of the file in the jar contains a specific string ($LOOK_FOR), but don’t care about which file, you can do this with unzip, here’s a small test:

$ echo hello > a
$ echo world > b
$ jar cf qq.jar a b
$ jar tf qq.jar
META-INF/
META-INF/MANIFEST.MF
a
b
$ unzip -p qq.jar|grep hello
hello

With the -p option, the files are unzipped to pipe (stdout).

If you want to know in which file the string is, I don’t think you can do anything better than unpack.