Intro 6 Flashcards
644
user: read/write
group, other: read
used for files
600
user: read/write
group, other: none
used for files
755
user: read/write/execute
group, other: read/execute
used for directories, programs
700
user: read/write/execute
group, other: none
used for directories and programs
711
user: read/write/execute:
group, other: execute
used for directories
You can list the contents of a directory if it’s readable, but you can only access a file in a directory if the directory is _______.
executable
Your system may have links that point to other links, which are called _______.
chained symbolic links
Symbolic links can cause headaches when you don’t know that they exist. For example, you could ____
easily edit what you think is a copy of a file, but is actually a symbolic link to the original.
Don’t confuse the syntax of symbolic link creation!
ln -s target linkname
not
ln -s linkname target!
How do you uncompress file.gz and remove the suffix?
gunzip file.gz
How do you compress a file with GNU Zip?
gzip file
Unlike the zip programs for other operating systems, gzip does not _______.
create archives of files
tar extract mode flag
x
e.g. tar xvf archive.tar
When using extract mode, remember that tar does not ______ after extracting its contents
remove the archived .tar file
table of contents mode for tar
t
When unpacking, consider using the _ option to preserve permissions.
p
The p option is the default when working as the superuser. If you’re having trouble with permissions and ownership when unpacking an archive as the superuser, make sure that you _____________. Although you may only want to extract a small part of an archive, _____________, and you must not interrupt the process because _____
are waiting until the command terminates and you get the shell prompt back
tar must run through the whole thing
it sets the permissions only after checking the entire archive
What two commands unzip compressed tarballs?
gunzip file.tar.gz
tar xvf file.tar
How can you unpack a compressed archive with one line using zcat?
zcat file.tar.gz | tar xvf -
What is the zcat command?
The same as gunzip -dc where the -d decompresses and the -c sends the results to standard output
What is a .tgz file extension?
The same as a .tar.gz file (it’s meant to fit into FAT (MS-DOS-based) filesystems.
____, while marginally slower than gzip, often compacts _____ a little more, and it is therefore increasingly popular in the distribution of source code.
bzip2
text files
What is the decompressing program from bzip2?
bunzip2
What is the bzip2 compression/decompression option for tar?
j
A new compression program named __ is also gaining popularity. The corresponding decompression program is ___.
xz
unxz
If you encounter a file that ends in .Z, ____.
you have found a relic created by the compress program, which was once the Unix standard.
What are the nine subdirectories of root?
bin dev etc usr home lib sbin tmp var
What are the two subdirectories of var?
log
tmp
What are the six subdirectories of usr?
bin man lib local sbin share
