How to pass grep result to a varible so i can use it with exec tar command?

Question

I am trying to compress all folder in dir based on some regex so I used grep to filter out the output now i need to use tar and folder name.

For example I want to .tar.gz each top level directory to its own archive. Dir name must start with "web_" and not end with ".tar.gz".

How can I catch grep output to a varibel so it looks like this:

find . -maxdepth 1 -mindepth 1 -type d -print | grep -v \.tar\.gz$ | grep ^\./web_ | exec tar -czf $name.tar.gz $name

or with ls -h

ls -h | grep -v \.tar\.gz$ | grep ^web_ | exec tar -czf $name.tar.gz $name

Selection "find ...":

root@4a94aef49e3a:/home# find . -maxdepth 1 -mindepth 1 -type d -print | grep -v \.tar\.gz$ | grep ^web_
./web_demozip1
./web_demozip2

Selection "ls -h":

root@4a94aef49e3a:/home# ls -h | grep -v \.tar\.gz$ | grep ^web_
web_demozip1
web_demozip2

Example:

# fixed name works but its overwrite itself so I need to catch a var from grep
ls -h | grep -v \.tar\.gz | grep ^_web | exec tar -czf web_demozip1.tar.gz web_demozip1

root@4a94aef49e3a:/home# pwd
/home
root@4a94aef49e3a:/home# tree .
.
├── web_demozip1
│   └── somefile.txt
├── web_demozip1.tar.gz
└── web_demozip2
    └── somefile.txt

Answer 1

You don't need to filter find results using grep. Use the filter capabilities of find instead.

find . -maxdepth 1 -mindepth 1 -type d \
  -name 'web_*' \
  -exec tar czf {}.tar.gz {} \;

find can also filter using regex, but it is not needed for your example. See here how to do.

Answer 2

If you just want to archive each directory in the current directory, one tarball per directory, I would go with a shell loop:

for dir in ./web_*/; do
    tarname=${dir%/}.tar.gz
    tar -czf "$tarname" "$dir"
done

The trailing slash on the glob (./web_*/) makes it match only directories, and the ${dir%/} returns the string with that suffix removed and a directory called like that is probably an error anyway.

Note that I dropped the condition checking the names against the .tar.gz suffix, since we're already looking only at directories and those are probably files. If you really do have directories named like that, you could add [[ $dir == *.tar.gz/ ]] && continue as the first line in the loop. (In Bash/ksh/zsh.)

If you want more complex patterns, look into Ksh-style extended globs in Bash (shopt -s extglob), or zsh's own extended globs in zsh.

Answer 3

Using xargs

I also found out that i can use XARGS not sure if this is a good aproach so let me know in the comment what you think of this. I am pretty sure that i should go with @ilkkachu or @pLumo solutions but just to prove it can be done:

cdate=$(date '+%Y-%m-%d-%H-%M')
ls -h | grep -v \.tar\.gz$ | grep ^web_ | xargs -I {} tar -czf {}_$cdate.tar.gz {}

Which would output:

root@4a94aef49e3a:/home# tree .
.
├── web_demozip1
│   └── somefile.txt
├── web_demozip1_2021-08-23-14-43.tar.gz
├── web_demozip2
│   └── somefile.txt
├── web_demozip2_2021-08-23-14-43.tar.gz
├── web_ spacedir3
│   └── somefile.txt
└── web_ spacedir3_2021-08-23-14-43.tar.gz