Saturday 16 October 2010

Compress/Decompress commands: Zip, TAR, TAR.GZ, TAR.BZ2

ZIP

To compress a directory with zip do the following:

# zip -r archive_name.zip directory_to_compress

Here’s how you extract a zip archive:

# unzip archive_name.zip

TAR

# tar -cvf archive_name.tar directory_to_compress

And to extract the archive:

# tar -xvf archive_name.tar.gz

This will extract the files in the archive_name.tar archive in the current directory. Like with the tar format you can optionally extract the files to a different directory:

# tar -xvf archive_name.tar -C /tmp/extract_here/

TAR.GZ

This format is my weapon of choice for most compression. It gives very good compression while not utilizing too much of the CPU while it is compressing the data. To compress a directory use the following syntax:

# tar -zcvf archive_name.tar.gz directory_to_compress

To decompress an archive use the following syntax:

# tar -zxvf archive_name.tar.gz

This will extract the files in the archive_name.tar.gz archive in the current directory. Like with the tar format you can optionally extract the files to a different directory:

# tar -zxvf archive_name.tar.gz -C /tmp/extract_here/


TAR.BZ2

This format has the best level of compression among all of the formats I’ve mentioned here. But this comes at a cost – in time and in CPU. Here’s how you compress a directory using tar.bz2:

# tar -jcvf archive_name.tar.bz2 directory_to_compress

This will extract the files in the archive_name.tar.bz2 archive in the current directory. To extract the files to a different directory use:

# tar -jxvf archive_name.tar.bz2 -C /tmp/extract_here/

source

create or delete mysql databases

- To backup mysql database
mysqldump -u username -p databasename > /path/to/dbfile.sql
- To restore a backed up mysql databas

mysql -u username -p databasename < /path/to/dbfile.sql

Convert avi files to mp4 using ffmpeg

ffmpeg -i input.avi -f mp4 -strict experimental -vcodec mpeg4 -maxrate 1000 -b 700 -qmin 3 -qmax 5 -bufsize 4096 -g 300 -acodec aac -ab 192 -s 320x240 -aspect 4:3 output.mp4





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