Bash

Random bash tips and tricks to (try to) use Bash properly and efficiently...

Loops

To iterate over a sequence of numbers:

1. With a know fixed upper limit

   for i in {1..5}; do
       echo $i;
   done

2. With a possibly unknown upper limit

   END=5
   for i in $(seq 1 $END); do
       echo $i;
   done

3. If seq can't be used

   END=5
   for ((i=1;i<=END;i++)); do
       echo $i
   done

[ref]

Tar archives manipulation

Listing content

To list the content of an archive without extracting, use the --list/-t option:

tar --list --file <my-archive.tar>
tar -tf <my-archive.tar>

Creating archives

To create an archive, use the --create/-c option:

tar --create --file <my-archive.tar> <file1> <dir1>
tar -cf <my-archive.tar> <file1> <dir1>

Extracting the content

To extract the files of an archive, use the --extract/-x option:

tar --extract --file <my-archive.tar>
tar -xf <my-archive.tar>

This will extract all the content of the archive in the current folder

To extract in a different folder:

tar -xf <my-archive.tar> -C </my/folder>

Note: the folder needs to exists first.

To extract only specific files:

tar -xf <my-archive.tar> <file1> <dir1>

Note: The name of the files and/or dirs to extract must be the same as listed using the --list option.

Other

To manipulate .tar.gz archives, add the -z option to all commands.

By default, all commands will read from stdin or write to stdout, allowing incoming and outgoing piping. To read to or from an existing archive, use the --file/-f option.