Questions dealing with Ubuntu's layout of files, permissions, and files that reside in special locations on disk.

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22
votes
4answers
51k views

What does /dev/null mean in a shell script?

I've started learning bash scripting by using this guide: http://www.tldp.org/LDP/abs/abs-guide.pdf However I got stuck at the first script: cd /var/log cat /dev/null > messages cat /dev/null >...
19
votes
7answers
22k views

How to determine where biggest files/directories on my system are stored?

I was wondering how do you know where the largest files in my system are stored. For example--- Disk Space Used: 1GB Java: 500MB Java Percentage: 50% maybe represented in a pie chart. Maybe? I know ...
2
votes
3answers
8k views

Why can not change the file /proc/sys/net/ipv4/ip_forward?

$ sudo echo 1 >/proc/sys/net/ipv4/ip_forward bash: /proc/sys/net/ipv4/ip_forward: Permission denied then I try to get write privilege, also failed. $ sudo chmod a+wx /proc/sys/net/ipv4/...
63
votes
2answers
36k views

Whats the .local folder for in my Home Directory

What is the ~/.local folder good for and is it safe to remove the content within this folder?
0
votes
1answer
62 views

Desktop shortcuts getting corrupted in Ubuntu 14.04 LTS

If I create a desktop shortcut in Ubuntu, for my folder(s) off my local drive, and when I login the next time, the shortcut link will be EXPIRED! If I try clicking that link, I get a message that the ...
1
vote
2answers
34 views

File system goes read-only when using file explorers

I have a problem with my 15.10 system and it goes as follows: When using Nemo or Nautilus (these are the two I've tried) works fine as long as I explore my home directory only. Visiting 'File System'...
2
votes
2answers
95 views

mounting error to access the drives in ubuntu 15.04

While trying to mount the drive it showing me an error like below...and  drive is not being mount ... “ Error mounting /dev/sda3 at /media/ubuntu/B840AE6C40AE30D4: Command-line `mount -t "ntfs" -o "...
15
votes
2answers
12k views

Why can't I copy a 5G file?

I'm trying to backup my VirtualBox, but when I try to copy the .VirtualBox directory to my external hard drive I get an "File too large" error: [130 amanda@luna ~]$ cp -r .VirtualBox /media/LACIE/...
4
votes
3answers
545 views

Size of device file ( missing in ls -l output )

When I try to print the device file output shows binary data in hexadecimal format. But upon doing a ls -l /dev/sda I get: brw-rw---- 1 root disk 8, 0 Jan 29 12:29 /dev/sda I don't ...
1
vote
1answer
32 views

Mount a disk at different points

What if I mount the same disk at two locations using different file systems? Will they just be like hardlinks referring to the same location or would it cause any issues? ex: # mount -t ext3 /dev/...
16
votes
4answers
35k views

How do I change UUID of a disk to whatever I want?

I have an unique situation where I need to change UUID of usb flash drive to previous UUID. I formatted it and obviously number changed... I've ubuntu server setup with 1TB hdd, and 4GB usb flash ...
1
vote
1answer
68 views

Switching back to read-only filesystem

I am using the Nexus 4 with UbuntuTouch installed. I switched to a writable filesystem by this command: sudo mount -o remount,rw / and it worked perfectly. How to switch back correctly to read-...
0
votes
3answers
131 views

How to make a line of directories with one command?

With the mkdir command if I want this location to exist ~/test/panda/fat when only the ~ part of it exists so far I have to do something like this: mkdir ~/test mkdir ~/test/panda mkdir ~/test/panda/...
8
votes
3answers
4k views

What can I move to RAM drive to have the system working faster?

Which files/directories can I move to RAM drive to have the system working faster? I'm planning to upgrade my laptop's memory to 8GB soon, so I'll have some fast memory to use. How to configure the ...
0
votes
1answer
83 views

Recover unreadable directory on ext4 partition

One of my directories in a ext4 filesystem on my SSD became unredable and I need to recover the files. Here is what I did to crash the filesystem: I accidentally created 1.5 million small files in ...
0
votes
0answers
48 views

mount xbox 360 formated disk

I have a game save data on a usb pen drive. Ubuntu doensnt recognize the disk file system though. I used the command fdisk -l, and tried installing netware 386 packages, but the disk still wound ...
143
votes
1answer
98k views

Differences between /bin, /sbin, /usr/bin, /usr/sbin, /usr/local/bin, /usr/local/sbin [duplicate]

I'm running an Ubuntu Server 13.04, but I see the same on a 12.04: I have six directories with command files. These are: /bin /sbin /usr/bin /usr/sbin /usr/local/bin /usr/local/sbin What are the ...
1
vote
1answer
144 views

How to format a FAT32 USB as EXT4

I have a USB device /dev/sda1 and I want to format it as ext4. I have tried sudo mkfs.ext4 /dev/sda1 It gives warning, goes ahead and completes formatting without error. But when I check it using ...
1
vote
1answer
59 views

Accidentally Wiped Root Partition - System Still Running

Alright, this is one of those times when I am are saying... Breathe deep, don't panic. What happened? As a usual part of leisurely tinkering with my system, I was trying write a 24.5 MB img file to ...
1
vote
1answer
79 views

After update chrome won't open desktop is read only

I'm running Ubuntu 15.10 and just did a software update via the software update manager. Now chrome will not open neither will Firefox and if I try to copy anything to my desktop I get an error ...
2
votes
3answers
103 views

Why are there redundant directories for .desktop files?

I know that the .desktop files of installed applications will be found in /usr/share/applications. Today, I came across the directory /usr/share/app-install/desktop. It contains the same .desktop ...
41
votes
3answers
59k views

How do I use OverlayFS?

This answer and email message indicate that something called "OverlayFS" is available in Ubuntu 11.10 and will forcefully replace aufs in Ubuntu 12.04. How do I use it? Where is its documentation?
1
vote
0answers
26 views

Directory converted to a file

I have an external HD formatted to ext4. Somehow a directory is now showing up as a file (i.e. it is missing the 'd' in the attributes). fsck does not show any errors. I don't believe that the ...
0
votes
1answer
38 views

WD Passport external device not recognized

I am getting following error when I connect my external HDD. Error mounting: mount exited with exit code 13: The disk contains an unclean file system (0, 0). The file system wasn't safely closed on ...
0
votes
0answers
161 views

“My Passport” USB Drive corrupted

My Passport drive corrupted. When I type: dmesg | tail I get: [ 667.778316] sd 6:0:0:0: [sdb] CDB: Read(10) 28 00 00 00 00 00 00 00 08 00 [ 667.778321] blk_update_request: I/O error, dev sdb, ...
0
votes
0answers
51 views

SFTP access and editing files outside the home folder

I would like to be able to edit all files on Ubuntu server 14.04 using Filezilla and SFTP. Is there another way to do that except connecting with root user ? If I connect with other user, then I ...
1
vote
1answer
658 views

/var/log taking up 8.9 GB! What should I do? [duplicate]

I am running Ubuntu 14.04 on my ASUS N550JV laptop. Just today I got a pop-up notification telling me that there were less than 100 MB in my root partition. I checked it and find /var/log is taking up ...
8
votes
4answers
44k views

Why has my file-system turned read-only after updates?

I'm running 11.10 and I applied some updates. After that whenever I use my computer, I can, but only for about 2 or 3 minutes before it becomes read-only. Any sudo command entered gives me the ...
0
votes
0answers
2k views

blk_update_request: I/O error, dev fd0, sector 0

This happened after a kernel update. Whenever I try to boot, my computer says "Error getting authority: Error initializing authority: Could not connect: No such file or directory (g-io-error-quark, 1) ...
2
votes
0answers
48 views

Mounting VFAT SD card on Ubuntu 14.04 not possible w/ x-gvfs-show option? [duplicate]

[Ubuntu 14.04.3 x86_64] I have a 128MB SD card that I want to use as a read-only tripwire binary and database volume. Using UDisks I reformatted (complete wipe) that card with FAT-16 bit version as ...
0
votes
0answers
114 views

Proper way to mount a hfs+ dive for read and write

So I have this drive from my old Mac Pro which contains a lot of data (about 1.5TB). I switched to a Linux box (running Ubuntu 15.10) and now I need r/w access to it. I got it working using this ...
3
votes
1answer
376 views

How to list compression ratio on compression enabled btrfs?

I enabled compression on a btrfs volume. Now how do I know the compression ratio of files or directories? Or at least the overall stats?
2
votes
3answers
6k views

Where in linux file system can i see files of Hadoop HDFS?

I am a just data analyst hails from non cs background (not a hardcore system programmer) working on linux OS. While exploiting analysis using hadoop, a question was coming to my mind that ... / is a ...
0
votes
0answers
38 views

Partition system id FDISK

if I change a partition system id to FAT16 with fdisk command and make another file system such as ext2 on that partition with mkfs command what is problem? every thing is ok ! so what does (partition ...
24
votes
3answers
7k views

What does `~/ ` mean?

I'm new to Linux and Ubuntu. People keep using ~/filename in their answers to my questions. What does ~/ mean?
47
votes
1answer
25k views

What is the rationale for the `/usr` directory?

What is the rationale for the "unix system resources", or /usr directory, as described here, which duplicates many of the directory names under the root directory /? My purpose: I'm installing Oracle ...
14
votes
5answers
10k views

Is NTFS-3G safe for writing?

These days, I have to use the NTFS-3G driver to write to an NTFS drive (which will later be used in Windows). But I still remember the olde times of Linux ntfs driver which clearly said in the docs: '...
1
vote
1answer
757 views

Mount FAT32: Can't find a valid FAT filesystem

Xubuntu 14.04. nfts-3g is installed. /dev/sdc is the Flash drive. I have created new partition with fdisk (tried with cfdisk too). Tried with W95 FAT32 code and W95 FAT32 (LBA) code. ("b" and "c" in ...
2
votes
1answer
2k views

ramdisk, compressed, writeable, no swap

I need a ramdisk who handle transparent realtime compression on write and decompression on read. Example : I use /dev/shm, or I create a new tmpfs, mount it writeable and compressed. I wrote and ...
10
votes
1answer
907 views

Can I hide files so that they are hidden on both Windows and Linux?

I have my computer set up to use the same home folder / user profile for Linux and Windows. As a consequence I have files like NTUSER.DAT that are hidden on Windows showing up when I ls and in my file ...
4
votes
3answers
3k views

recover LVM after hdd crash

Yesterday, one hdd of my LVM crashed (smart-error) The Machine has the following setup: - 4 hdds - 1 Partition Raid10 (System, 4*50GB) - 1 Partition normal (/boot, 200MB, sda) - 1 Partition LVM2 (...
0
votes
0answers
24 views

GUI for managing persistent network filesystem mounts

Is there a GUI for managing persistent network filesystem mounts? I presume it would be a thin GUI layer on top of /etc/fstab file?
3
votes
2answers
488 views

Utility says there's no more free disk space, when there's plenty

Somehow my system is in a pickle. $ sudo apt-get install -f Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The ...
7
votes
6answers
859 views

How to count the total number of files/folders on a system?

How can I count the number of all files/folders that exist on a system, using the command-line? I can find it out using a GUI, simply by opening the properties window for the entire / folder, but it ...
0
votes
1answer
23 views

is there anything else to fix ext4 14.04 encrypted root? should I stay with ext4 or is another more likely to last longer?

I can't get 14.04 to boot but from a 15.10 partition I can: ~$ sudo fsck.ext4 -v /dev/mapper/vgcrypt-lvroot e2fsck 1.42.12 (29-Aug-2014) /dev/mapper/vgcrypt-lvroot contains a file system with errors,...
0
votes
3answers
75 views

Is it safe to use a disk after a successful fsck?

I had not used my venerable ThinkPad T400 for about 2 weeks. I booted normally but was told to run fsck manually because of errors. I'm using 12.04 and the disk in question is ext4, a Samsung Evo 840,...
1
vote
1answer
63 views

Why doesn't my dvd/cd-rom show up with the “mount” command?

So, mount is supposed to show all file systems mounted in the OS file system. However, this is not the case for my system: the drive is called cdda//:sr0/, and no part of this is revealed in the mount ...
0
votes
2answers
21 views

Two Linux OSes on same machine - can edit files on the other OS safely?

I originally had an Xubuntu 14.04 (32 bit) on my machine. I have now also installed a Ubuntu 14.04 (64 bit) on the same machine and plan to migrate eventually there. In both OSes I have access to ...
0
votes
2answers
138 views

Cleared and Unformatted partitions in GParted

I was formatting my drive and found a partition system named cleared and unformatted. What are those partitions and why they are in GParted app ?
14
votes
8answers
12k views

How to create an encrypted partition?

I am trying to create an encrypted partition, and while I format it I get the option to choose the partition type (fat/ext2/ext3/ext4/xfs/reiserfs/minix/ntfs). Is there any benefit of choosing one ...