Linux/Compression tools

tar

• create .tar.gz

tar -czvf file.tar.gz directory        # pack directory 
                                       # (c):create (z):gzip (v):verbose (f):file

tar -czf file.tar.gz -C /var/www .     # remove parent directory path

• list contents

tar -ztvf my-data.tar.gz               # (z):gzip (t):list (v):verbose (f):file

• extract (untar)

tar -xvf archive.tar.gz                # (x):extract (v):verbose (f):file

benchmark

• Compressing 6144MB kvm image (RAW, 2,7GB used)

Command	Arguments	compressed size [MB]	time [s]	additional size [MB]
pigz	--best	1526	259.65	533
pigz	--fast	1667	28.06	674
cat	> target	6144	60.80
copy		6144	59.36
7z	a -t7z -mx1 -si	1333	359.66	340
7z	a -t7z -mx9 -si	993	1360.15	0
7z	a -m0=lzma2 -si	1137	551.40	144
7z	a -m0=lzma2 -mx9 -si	1006	788.00	13

• benchmark script

#!/bin/bash
COMPRESSCMD="pigz -9"
DESC="pigz-best"

START=$(date +%s.%N)
cat image.img | $COMPRESSCMD > /backup/$DESC.img.gz
END=$(date +%s.%N)
DIFF=$(echo "$END - $START" | bc)
echo "$DIFF" > /backup/$DESC.log