(Un/De)compress a string in bash?

问题

Is it possible to compress/decompress a string in bash using stdin/stdout ?

I tried this but apparently it is not supported ?

hey=$(echo "hello world" | gzip -cf)
echo $hey # returns a compressed string
echo $hey | gzip -cfd
gzip: stdin is a multi-part gzip file -- not supported

I'm not well versed in linux but I read other compression utilities man pages and couldn't find a solution?

回答1:

When you do:

hey=$(echo "hello world" | gzip -cf)

You don't have same same bytes in variable hey as you have in /tmp/myfile created by:

echo "hello world" | gzip -cf > /tmp/myfile

You get "gzip: stdin is a multi-part gzip file -- not supported" error simply because you have broken compressed data which cannot be uncompressed.

The VAR=$(...) construction is designed for working with text. This is why you get extra trailing trim for example.

回答2:

If 33% compression rate loss is acceptable for you, then you can store base64 encoded compressed data:

me$mybox$ FOO=$(echo "Hello world" | gzip | base64 -w0) # compressed, base64 encoded data
me$mybox$ echo $FOO | base64 -d | gunzip # use base64 decoded, uncompressed data
Hello world

It will work, but each 3 (compressed) bytes will be stored in 4 bytes of text.

来源：https://stackoverflow.com/questions/7538846/un-decompress-a-string-in-bash