Chapter 4 Managing Files

Question 1

A few characters have special meaning and should never be used in file names. What are they? pg 179

Answer 1

*,? / "

Question 2

What is a wild card? pg 180

Answer 2

A wildcard is a symbol or set of symbols that stand in for other characters.

Question 3

What are 3 common classes of wildcards in Linux?

Answer 3

• Star, ? Question Mark, Square or bracketed

Question 4

What does the cp command do?

Answer 4

copies a file

Question 5

What are the 3 operating modes of cpio? pg 191

Answer 5

Copy-Out, Copy-In,Copy Pass

Question 6

What does the mkdir command do? ?pg 198

Answer 6

Creates a Directory

Question 7

What does the rmdir command do? pg 198

Answer 7

Destroys the directory

Question 8

which command will delete an entire directory tree? pg 198

Answer 8

-p or –parents Example(rmdir -p one/two/three)

Question 9

What is the sticky bit? pg 205

Answer 9

its used to protect files from being deleted by those who don’t own the files.

Question 10

what are the prerequisites of using Linux’s disk quota system?

Answer 10

Linux’s disk quota system requires support in the Linux kernel for the file system on which quotas are to be used. you must also run the quotation command typically from a start up script to enable this feature.

Question 11

Describe linux file ownership system?

Answer 11

Every file has an owner and a group, identified by a number. File permissions can be assigned independently to the files owner,the files’s group, and to all other users.

Question 12

True or False pg 190 True

Answer 12

the xz compression tool has gained so much popularity, the linux kernel is now compressed with it.

Question 13

Linux-native file systems maintain three time stamps for every file: what are the three?

Answer 13

Last File Modification time,Last inode change time,Last access time

Question 14

/root

Answer 14

root is the user name or account that by default has access to all commands and files on a Linux or other Unix-like operating system. It is also referred to as the root account, root user and the superuser.

Question 15

summarize Linux’s directory manipulation commands?

Answer 15

the mkdir command creates a new directory. and rmdir deletes a directory. You can also use many file manipulation commands such as mv and rm

Question 16

if you want to search a directory and perhaps some limited number of sub directories what can you use?

Answer 16

-maxdepth

Question 17

on Page 221 there are 5 directories that should not be on their own partitions. Name them?

Answer 17

/bin
/dev
/etc
/lib
/sbin

Question 18

A superuser can turn quotas on at anytime by using what command? pg 214

Answer 18

quotaon

Question 19

A superuser can turn quotas off at anytime by using what command? pg 214

Answer 19

quotaoff

Question 20

What is symbolic mode?

Answer 20

its a set of codes related to the string representation of the permissions.

Question 21

Tail Merging pg 213

Answer 21

is a feature of some computer file systems which allows large blocks or allocation units to be used while making efficient use of “slack” space at the end of large files, space which would otherwise be lost for other use to internal fragmentation.

Question 22

Set User ID (SUID)

Answer 22

is a special type of file permissions given to a file. Normally in Linux/Unix when a program runs, it inherits access permissions from the logged in user. SUID is defined as giving temporary permissions to a user to run a program/file with the permissions of the file owner rather that the user who runs it. In simple words users will get file owner’s permissions as well as owner UID and GID when executing a file/program/command.

Question 23

Set Group ID (SGID)

Answer 23

is a special type of file permissions given to a file/folder. Normally in Linux/Unix when a program runs, it inherits access permissions from the logged in user. SGID is defined as giving temporary permissions to a user to run a program/file with the permissions of the file group permissions to become member of that group to execute the file. In simple words users will get file Group’s permissions when executing a Folder/file/program/command.

Question 24

What does FHS stand for in Linux?

Answer 24

File system Hierarchy Standard(FHS)

Question 25

what is a symbolic link?

Answer 25

its a separate file whose contents point to the linked to file.

Question 26

force overwrite

Answer 26

the -f or –force options forces the system to overwrite any existing files.

Question 27

interactive mode

Answer 27

-i or –interactive option causes cp to ask you before overwriting any existing files.

Question 28

recursive copy

Answer 28

-r or –recursive option and specify a directory as the source option, the entire directory, including sub directories.

Question 29

Archive Copy

Answer 29

-a or –archive option is similar to -R but it also preserves ownership and copies links as is.

Question 30

Update Copy

Answer 30

-u or –update options tells cp to copy the file only if the original is newer than the target or if the target doesn’t exist.

Question 31

tar command (tar) tape archiver

Answer 31

archive data to other media

Question 32

tarballs

Answer 32

are often used for transferring multiple files between computers in one step, such as when distributing source code. A tarball is an archive file created by tar and typically compressed with gzip, xz, or bzip2

Question 33

c, –create

Answer 33

x, –extract, –get

Question 34

A, –catenate, –concatenate

Answer 34

Append tar files to an archive.

Question 35

d, –diff, –compare

Answer 35

Append tar files to an archive.

Question 36

–delete

Answer 36

Delete from the archive. (This function doesn’t work on magnetic tapes).

Question 37

r, –append

Answer 37

Append files to the end of a tar archive.

Question 38

t, –list

Answer 38

List the contents of an archive.

Question 39

–test-label

Answer 39

Test the archive label, and exit.

Question 40

u, –update

Answer 40

Append files, but only those that are newer than the copy in the archive.

Question 41

x, –extract, –get

Answer 41

Extract files from an archive.

Question 42

copy-out mode

Answer 42

This mode,activated by use of the -o or –create option,creates an archive and copies files into it.

Question 43

copy-in mode

Answer 43

you activate copy-on mode by using the -i or –extract option. This mode extracts data from an existing archive. If you provide a filename or a pattern to match, cpio extracts only those files whose names match the pattern you provide.

Question 44

copy pass mode

Answer 44

this mode is activated by the -p or –pass though option.

Question 45

link

Answer 45

is a way to give a file multiple identities, similar to shortcuts in windows and aliases in Mac OS.

Question 46

Three reasons Linux employs links?

Answer 46

1) help make files more accessible
2) give commands to multiple names
3) to enable programs that look for the same files in different locations to access the same files.

Question 47

Hard links

Answer 47

are produced by creating two directory entries that point to the same file( more precisely the same mode)

Question 48

ln command

Answer 48

creates hard links by default. The source file must exist before a hardlink is created.

Question 49

permission bits

Answer 49

individual permissions such as execute access for the file owner are often referred to as permission bits.

Question 50

/bin

Answer 50

this directory contains certain critical executable files such as ls,cp and mount.

Question 51

/sbin

Answer 51

/sbin is a standard sub directory of the root directory in Linux and other Unix-like operating systems that contains executable (i.e., ready to run) programs. They are mostly administrative tools, that should be made available only to the root (i.e., administrative) user.

Question 52

/lib

Answer 52

The /lib directory contains kernel modules and those shared library images (the C programming code library) needed to boot the system and run the commands in the root filesystem, ie. by binaries in /bin and /sbin. Libraries are readily identifiable through their filename extension of *.so. Windows equivalent to a shared library would be a DLL (dynamically linked library) file. They are essential for basic system functionality. Kernel modules (drivers) are in the subdirectory /lib/modules/’kernel-version’. To ensure proper module compilation you should ensure that /lib/modules/’kernel-version’/kernel/build points to /usr/src/’kernel-version’ or ensure that the Makefile knows where the kernel source itself are located

Question 53

/opt

Answer 53

This directory is reserved for all the software and add-on packages that are not part of the default installation. For example, StarOffice, Kylix, Netscape Communicator and WordPerfect packages are normally found here. To comply with the FSSTND, all third party applications should be installed in this directory. Any package to be installed here must locate its static files (ie. extra fonts, clipart, database files) must locate its static files in a separate /opt/’package’ or /opt/’provider’ directory tree (similar to the way in which Windows will install new software to its own directory tree C:\Windows\Progam Files"Program Name”), where ‘package’ is a name that describes the software package and ‘provider’ is the provider’s LANANA registered name.

Question 54

/mnt

Answer 54

This is a generic mount point under which you mount your filesystems or devices. Mounting is the process by which you make a filesystem available to the system. After mounting your files will be accessible under the mount-point. This directory usually contains mount points or sub-directories where you mount your floppy and your CD. You can also create additional mount-points here if you wish. Standard mount points would include /mnt/cdrom and /mnt/floppy. There is no limitation to creating a mount-point anywhere on your system but by convention and for sheer practicality do not litter your file system with mount-points. It should be noted that some distributions like Debian allocate /floppy and /cdrom as mount points while Redhat and Mandrake puts them in /mnt/floppy and /mnt/cdrom respectively.

Question 55

/root

Answer 55

This is the home directory of the System Administrator, ‘root’. This may be somewhat confusing (‘root on root’) but in former days, ‘/’ was root’s home directory (hence the name of the Administrator account). To keep things tidier, ‘root’ got his own home directory. Why not in ‘/home’? Because ‘/home’ is often located on a different partition or even on another system and would thus be inaccessible to ‘root’ when - for some reason - only ‘/’ is mounted.

Question 56

/dev

Answer 56

/dev is the location of special or device files.

Question 57

/proc

Answer 57

/proc is very special in that it is also a virtual filesystem. It’s sometimes referred to as a process information pseudo-file system. It doesn’t contain ‘real’ files but runtime system information (e.g. system memory, devices mounted, hardware configuration, etc). For this reason it can be regarded as a control and information centre for the kernel. In fact, quite a lot of system utilities are simply calls to files in this directory. For example, ‘lsmod’ is the same as ‘cat /proc/modules’ while ‘lspci’ is a synonym for ‘cat /proc/pci’. By altering files located in this directory you can even read/change kernel parameters (sysctl) while the system is running.

Question 58

-gid

Answer 58

searches for files whose group ID is set to gid.

Question 59

whereis

Answer 59

it searches doe files in a restricted set of locations,such as standard binary files directories,library directories and ma pages directories.

Question 60

-size

Answer 60

you can search for a file of a given size with the -size n expression.