Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
57 Cards in this Set
- Front
- Back
|
Commands that require an argument will give this error when none is given.
|
Usage message
|
|
|
An Argument is a
|
token, such as a filename,text,number or object that a command acts on.
|
|
|
Arguments start numbered
|
0
|
|
|
option is a
|
argument that modifies the effect of a command.
|
|
|
You can have more then one option.
|
True
|
|
|
Hyphens in programs
|
GNU two hyphens, normally ONE
|
|
|
Usually you can list options in any order.
|
True
|
|
|
-h
|
human readable
|
|
|
Arguments that start with a hyphen
|
ls -- -l, ls ./-l, ls /home/alex/-1
|
|
|
Long listing a hyphen argument
|
ls -l -- -l
|
|
|
help option
|
--help
|
|
|
Control h
|
erase a character
|
|
|
control u
|
kill a line
|
|
|
control w
|
erase a word
|
|
|
a program has to appear first
|
False
|
|
|
Execute a executible in the working directory.
|
./file
|
|
|
ls -l
|
displays permissions. Long listing.
|
|
|
Shell does not
|
process command line arguments. It hands them off to the program.
|
|
|
standard output
|
a place that a program can send information
|
|
|
standard input
|
a place the program gets information from.
|
|
|
device file
|
usually in the /dev directory. Represents a peripheral(terminal,screen,printer or disk drive)
|
|
|
chch
|
changes your login shell
|
|
|
control d
|
end of file signal
|
|
|
>
|
redirect output signal
|
|
|
redirect output signal
|
redirects the output to a specific file then to the screen
|
|
|
Redirecting output can destroy a file
|
True
|
|
|
<
|
redirect input signal
|
|
|
redirect input signal
|
redirects the input to come from a specific file instead of the keyboard.
|
|
|
noclobber
|
stops you from accidentally overwriting a existing file using redirection.
|
|
|
override no clobber
|
>|
|
|
|
set -o noclobber
|
enables no clobber
|
|
|
set +o noclobber
|
disables no clobber
|
|
|
>>
|
append output symbol
|
|
|
append output symbol
|
adds new information to the end of the file leaving existing info intact.
|
|
|
/dev/null
|
data sink or bit bucket
|
|
|
redirect output that you don't want to see or keep too
|
/dev/null
|
|
|
|
|
connect standard output of a command to the input of another command.
|
|
|
sort can be used as
|
filter
|
|
|
Not all utilities can be used as a
|
filter
|
|
|
Tee
|
copies its standard input to a file and to a standard output
|
|
|
&
|
Used to run a command in the background.
|
|
|
Control Z
|
Suspends
|
|
|
To put a suspended job in the background
|
use the bg command followed by the job number.
|
|
|
fg
|
brings a back rounded app back to the foreground.
|
|
|
control c
|
interupt key
|
|
|
kill
|
kills a backgrounded process. With either PID or % and the job number.
|
|
|
ps
|
process status, utility to display pid #'s
|
|
|
?
|
causes the shell to generate file names
|
|
|
examples of ?
|
memo? =memo1, memox
|
|
|
*
|
matches any number of characters in a file including zero characters.
|
|
|
jobs
|
displays a list of currently running jobs
|
|
|
tr
|
maps one string of characters into another
|
|
|
memo[17a]
|
will search for memo1 memo7 and memoa
|
|
|
[a-zA-Z]
|
search for lowercase letters a-z and uppercase A-Z
|
|
|
builtin
|
utility that is built in to the shell.
|
|
|
info bash builtin
|
complete list of bash builtins
|
|
|
when running a builtin the shell does not fork a new process.
|
True
|
