Useful Linux Commands

Useful Linux Commands - I

Want to know your system name?

/bin/uname -n

Know where you are in your file system:

The command will print Present Working Directory

How do you create a shortcut in linux?

How to extract compressed files?

Downloading from a link can't be faster on any other OS :)

wget

Forgot which commands you ran?

history

Want to see whats your disk space usage?

df
df -h gives human formatted listing

Most important command to know more about the above commands - Need more help about the commands?

Comments

wget error–“zsh: parse error near &”

There is no doubt that I prefer wget way over any other type of downloads… Syntax: wget <DOWNLOAD_URL> If you get this error “ zsh: parse error near & ” then its probably because your download URL has a “&” so you should try giving your DOWNLOAD_URL in double quotes wget “<DOWNLOAD_URL>” If you are trying to download from a site which needs you to give your credentials then you can try giving it this way wget --http-user=<UserName> --http-password=<Password> “<DOWNLOAD_URL>” Hope this helps

Apache Commons StringUtils.isEmpty() vs Java String.isEmpty()

You might want to test for if a String is empty many a times. Before we jump onto the numerous solutions available let us take a look at how we define “Empty String” The difference in the two methods given by Apache and Java are dependent on how we define an empty string. Java String.isEmpty returns a boolean true if the string’s length is zero. If the string has null it throws NullPointerException Apache StringUtils.isEmpty returns a boolean true if the string is either null or has length is zero Thus its purely dependent on how you are defining “empty string” in your program which will decide which function to use…BTW if you want to skip using Apache Commons funciton and would want to stick to java then you can have your own function like this: public static boolean isEmptyOrNull(String strStringToTest) { return strStringToTest == null || strStringToTest.trim().isEmpty(); }

How to Unpack a tar file on Windows?

On Windows: You can download a simple command line tool to do this. You can download the tool from here Usage can be found on the website but pasting it here too for convenience: C:\>TarTool.exe Usage : C:\>TarTool.exe sourceFile destinationDirectory C:\>TarTool.exe D:\sample.tar.gz ./ C:\>TarTool.exe sample.tgz temp C:\>TarTool.exe -x sample.tar temp TarTool 2.0 Beta supports bzip2 decompression for files with extensions like tar.bz2 and .bz2 . TarTool -xj sample.tar.bz2 temp or TarTool -j sample.bz2 Download TarTool 2.0 Beta from here Unpack a .txz file on Windows Use the 7zip tool to unpack a .txz file on windows On Linux: You can use the bzip2 and tar combined to do this… for ex: bzip2 –cd <tar.bz_fileName> | tar –xvf - This will unpack the contents of the tar.bz file Happy Un-Tar-ing

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