Error – getcwd failed!

You run a command on command line and receive a mysterious error message:

sh: 0: getcwd() failed: No such file or directory

Possible explanation is that the directory you were working in has been deleted by some other process and indeed just does not exist anymore. Move, for example by typing “cd”, and continue working elsewhere.

Advertisements

Invalid command RewriteEngine

After (re-)installation of Apache2 the browser greets you with error 500 “Internal Server Error” and Apache2 error log file contains message “Invalid command ‘RewriteEngine’, perhaps misspelled or defined by a module not included in the server configuration”.

Well, you might want to enable mod_rewrite, which is disabled by default:

  • a2enmod rewrite
  • service apache2 restart

Missing php-mbstring

After (re-)installing PHP and attempting to run a script, you may see an error message saying “PHP Fatal error: Uncaught Error: Call to undefined function mb_strtoupper()”.

Well, you may be missing the php-mbstring extension to PHP. Simply install it by:

  • sudo apt-get install php-mbstring

Symbolic links in Nautilus/Caja

It is very irritating that there seems not to be an option for creating links to files in Gnome file manager Nautilus and its derivatives, like Caja. After all, this is such a useful feature, giving the user so much more convenience when working in Linux as compared to Windows.

It turns out, that the feature is actually there, but for some weird reason it is not available from the GUI.

Just press Ctrl+Shift and drag and drop your file between file manager’s windows, and a symbolic link will be created instead of copying the file.

As an alternative, you can do the dragging with the middle mouse button. Then on drop you will be shown a context menu with “Link Here” as an option.
 


Is my system 32 or 64 bit?

On Linux, to find out if you have 32 or 64 bit CPU just type:

  • arch

Display processor information

Wondering what CPU you have got? Just type:

  •  lscpu

Or simply output the contents of this virtual file:

  • cat /proc/cpuinfo

Using HP LaserJet 2010 printer with Linux Mint

The problem: HP LaserJet 2010 printer gets recognized by Linux Mint but fails to print.

The solution:

  • Remove all automatically installed printers
  • sudo hp-setup -i

Let it download the HP plugin and accept defaults, then print test page (you must not be root or the print will fail).