glossary - programming

! 1. bang
2. not
More about ! at
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See also:
pipe, piping
bang
#! shebang More about #! at
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shuh-BANG
# 1. hash
2. comment mark
3. Convention for prompt for root user
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See also:
shebang
hash
% 1. per cent
2. Means all lines in the vi editor
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per CENT
- dash More about - at
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dash
. "dot"
1. source
2. Indicating here in a directory listing
3. The dot in a dot file name
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the three dots
dot
/ slash More about / at
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slash
: colon More about : at
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COLE-un
< > angle brackets More about < > at
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ANG-gul BRACK-et
@ 1. "at" or "at the rate" - used in an email address
2. php programming: the shuddup operator
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at, shud-dup
[ ] square brackets More about [ ] at
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SQWAR BRACK-et
\ backslash More about \ at
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back-slash
{ } curly brackets
Also called curly braces or curlies
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KUR-lee BRACK-et
abort the abnormal termination of a program "I hit ctrl-C to abort the program" More about abort at
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uh-BORT
absolute number See unsigned number More about absolute number at
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AB-so-loot NUM-ber
absolute path The complete pathname to a file, starting at the root (/) directory. Example:
/home/myname/journal.txt
The absolute path to journal.txt is /home/myname/
More about absolute path at
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See also:
relative filename, filesystem
AB-so-loot PATH
abstraction Scripts that use abstraction retain the same basic flow by placing the conditional execution statements within functions. When a function is called, it makes a decision as to what commands execute for a given platform. More about abstraction at
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ab-STRAK-shun
address In memory: the location of a particular byte. For disk or tape: the number of a block or sector. More about address at
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ADD-ress
address space The area of memory available to the running program. More about address space at
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ADD-ress space
algorithm A defined set of actions. More about algorithm at
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AL-go-rithum
anchoring expression Normally anhy part of a line will be matched by a regular expression. to match expressions that either begin or end a line, you need ot anchor the regular expression. The ^ character anchors regular expressions to the beginning of a line, whereas the $character anchors regular expressions to the end of a line. /^foo .*/ will match all lines that have foo at the beginning of the line. More about anchoring expression at
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ANK-or-ing ex-PRESH-un
applet A small program, often written in java, which usually runs in a web browser, as part of a web page. More about applet at
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APP-let
application Another word for a program More about application at
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ap-lih-KAY-shun
application program A program that performs a specific task (or set of tasks) in coordination with an operating system. The task may be anything from a calculator to a word processor to a database management program. More about application program at
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app-lih-KAY-shun pro-gram
argument This is not about disagreements!
1. In unix, arguments are the options to a unix command, also the filenames you want the command to operate on.
2. In programming, arguments are the values you pass to a function.
1. unix:
When you type
ls -l *.html
the -l and the *.html are arguments to the ls command.
More about argument at
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See also:
In programming, also called parameters
In shell command line, also called options or flags
AR-gyu-ments
array An ordered arrangement of units of data; a collection of scalars. Arrays are manipulated one unit at a time by using an index; other times the address ofthe first unit is used to refer to the array as a whole. An array can be organized into any number of dimensions, limited only by the capacity of memory and the limitations of the language. An array of more than one dimension is often called a matrix. More about array at
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uh-RAY - sometimes AIR-ray
array variable A structure to group scalar variables together. $myvar = array('dog', 'cat', 'horse', 'yak') More about array variable at
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See also:
index, key
arr-AY VAR-ee-ubl
artifical intelligence the ability of computers to reason in a manner similar to human beings. It is still largely a theoretical study. More about artifical intelligence at
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ar-tih-FISH-ul in-TELL-ih-juns
ASCII American Standard Code for Information Interchange. It is the set of binary representations ofthe standard characters (A-Z, a-z, etc.) that most computers and peripherals use. Compare to EBCDIC. More about ASCII at
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ASK-ee
assembler A program that converts assembly language source code to machine language. More about assembler at
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uh-SEM-blur
assembly language The symbolic equivalent of machine language, using meaningful mnemonics (e.g., READ, LOAD, STORE) to represent binary machine instructions. More about assembly language at
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uh-SEM-blee LANG-widge
assignment statement A statement that performs an operation on one or more operands and stores the result in a specified memory location. More about assignment statement at
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uh-SINE-ment STATE-ment
asynchronous I/O An input or output (I/O) operation that, once started, operatest independently of the starting program. Contrast with synchronous I/O More about asynchronous I/O at
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ay-SIN-kron-us eye-oh
awk A powerful pattern-matching language that allows you to modify input lines by manipulating the fields they contain. More about awk at
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awk
background A process usually runnikng at a lower priotity, and with its input disconnected from the interactive sesson. and input and output are usually directed to a file or to another process More about background at
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bak-ground
background process An automomous process that is running under unix without requiring user interaction. More about background process at
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bak-ground PRAH-cess
backup A copy of files on some storage medium, such as disk or tape. More about backup at
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BACK-up (noun), back-UP (verb)
backwards compatibility A quality of a new version of a language, operating system, or hardware such that programs that used to work onder the previous version will also work with this new one, More about backwards compatibility at
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BACK-wards com-pat-ih-BIL-ih-tee
basename The ending directory or file name in a path The basename of /usr/home/tashi is tashi
The basename of /www/site/news.html is news.html
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base-name
batch processing A method of executing programs under the control of the operating system, without a human user More about batch processing at
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batch PROH-cess-eeng
begin-end pair The pair of keywords which mark the start and end of a code block in a high-level language More about begin-end pair at
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be-gin-end PARE
binary A two-digit number system (zero and one). Ultimately, all data in memory consists of binary numbers – circuits which are either ON [1] or OFF [0]. More about binary at
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BYE-nuh-ree
binary operator An operator which requires two operands. More about binary operator at
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BYE-nuh-ree OP-ur-ay-tor
bit The smallest unit of memory: zero [0] or one [1]. Eight bits make one byte. More about bit at
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bit
block 1. In programming code, a section of structured code which is isolated from other parts of the program.
2. In a disk, the grouping of one or more disk file records into a unit that is read or written with one I/O operation. The size of the block is related to the physical characteristics of the I/O device - often 512 bytes in size. A disk is typically composed of many tens, or hundreds, of thousands of blocks of information.
More about block at
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See also:
i-node
block
block I/O Input from or ouput to a file or I/O device using groups of data. Contrast with record I/O. More about block I/O at
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block eye-oh
body 1. in programming, the set of commands executed by a loop is called the body of the loop.
2. In html, the body is the part of the html file between the <body> tags, containing the content that is shown on the web page.
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BAH-dee
boolean value See logical value More about boolean value at
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BOOL-ee-un VAL-you
boot A hardware operation that takes the computer from the "power on" state to a usable condition. Its major function is to locate and read in the operating system. More about boot at
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boot
break A control statement which causes the program to break out of the current if-then-else, do-while, or switch construction. More about break at
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brake
breakpoint A software trap set by the debugger in the running program. When the breakpoint is executed, it transfers control of the computer to the debugger. More about breakpoint at
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BRAKE-point
Brian Kernighan unix: regular expressions (grep), programming principles, typesetting, computer-aided instruction, C language, awk More about Brian Kernighan at
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BRI-un KURN-ih-gun
buffer A section of memory (usually defined as an array) that contains variable amount of data. The term is usually associated with I/O operations. More about buffer at
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BUFF-ur
bug An error in a program (from the english word for "insect"). More about bug at
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See also:
debug, debugger
bug
built-in A command whose code is part of the shell, as opposed to a utility that exists in a separate disk file, which must be read into memory separately. ls is a built-in command of most unix shells (such as bash) More about built-in at
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bilt-in
byte The smallest addressable unit of memory. It almost always consists of eight bits. 1024 bytes make one kilobyte (KB). More about byte at
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bite
C A structured language, developed by Bell Labs in the early 1980s, that is flexible enough to be used to write operating system code as well as application programs. C and its descendants (C++ and Java) are some of the most popular languages in use today. More about C at
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see
C++ A programming language descended from C, which is object-oriented. More about C++ at
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see-plus-plus
call An instruction which changes the program flow to another memory location while preserving the address of the instruction following the call. it is used to execute a subroutine, function, routine, or procedure. The return instruction changes the execution flow back to the instruction after the call. More about call at
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kall
call by reference A parameter passed to a subroutine as an address. The subroutine uses indirect addressing or pointer manipulation to access the data. The subroutine can also use this location as a means of passing complex data back to the caller. More about call by reference at
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kall by REF-ur-ense
carriage return A control character that moves the cursor back to the leftmost column on the screen, or the print head back to the left margin of the paper. Often abbreviated as CR. Represented in code by r. Usually combined with line feed. More about carriage return at
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KARE-rij ree-turn
central processing unit Also called a CPU. the central circuitry whic performs the individual software instructions. Includes circuits to locate data in memory. Also includes the internal registers. More about central processing unit at
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SEN-trul PRO-sess-eeng YUNE-it
character A letter, digit, punctuation mark, or symbol that can be typed in from a keyboard, displayed on a monitor, or printed by the printer. Standard ASCII characters do not need any special processing, but special characters might. More about character at
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KARE-ack-tur
child process See subprocess More about child process at
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CHILD PROH-sess
child shell See subshell More about child shell at
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child shell
chip An integrated circuit, the successor to transistors and vacuum tubes. A CPU is made up of one or more chips, as are memory boards and most other components of a modern computer. More about chip at
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chip
coder A programmer. More about coder at
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CO-dur
comma separated values The long way to say "csv" More about comma separated values at
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KOM-uh SEP-ur-ate-ed VAL-yous
command 1. unix: Each program in unix is also known as a command. Same thing.
2. shell: Also, the name of a program along with any arguments you specifiy to it. The text you type in the command line
3. programming: A line of code which performs some action.
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kum-MAND
command separator Some symbol to show where one command ends and another begins. The most common command separator is the semicolon  ;  More about command separator at
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kum-MAND SEP-ur-ay-tur
command substitution The process by which the shell executes a command and substitutes in the output of the command. More about command substitution at
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kum-mand sub-stih-TOO-shun
comment something in the source code of a program which is not code, but is for a human to read. Usually it is description of what the code is doing. In html, a comment is set off by the characters <-- and -->. More about comment at
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KOM-ment
compound command A list of commands separated by the command separator character. More about compound command at
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See also:
simple command
KOM-pound kum-mand
compound expresson Consists of one or more expressions More about compound expresson at
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KOM-pound ex-PRESH-un
computer file A file More about computer file at
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kom-pyoo-tur file
conditional execution Alters the execution of some code, based on the some parameter. Usually consists of an if statement. More about conditional execution at
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con-DISH-un-ul ek-seh-KYU-shun
conditional expression An expression which returns true or false, usually with some kind of if statement if (love unix) then
install
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kun-dish-un-ul ex-PRESH-un
control character A non-printing character – a code point (a number) in a character set that does not in itself represent a written symbol. Such as BEL (intended to cause an audible signal in the receiving terminal), SYN (a synchronization signal). More about control character at
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kun-TROL kare-uk-tur
control code See control character More about control code at
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kun-TROL kode
convention A practice or procedure widely observed in a group; the usual, accepted way of doing things. It's not a rule, nothing will break if you do it differently, but if you follow the convention, most people will understand it. More about convention at
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default
kun-VEN-chun
core dump When a program crashes, it can write an image of everything it has in memory at that time to the disk. This image is called a core file or core dump More about core dump at
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KOR dump
CPU Central Processing Unit More about CPU at
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see-pee-you
csv "comma separated values" A format for organising data, by separating the fields or values with commas 'dog', 'cat', 'rat' More about csv at
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See also:
database, tsv
see-ess-vee
data information, in any form: numbers, words, organised or unorganised More about data at
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See also:
database, filesystem
DAY-tuh or DAH-tuh
debugging hook A function or set of commands that executes only when script executes with a special argument. Debugging hooks provide a convenient method for tracing the execution of a script in order to fix problems. More about debugging hook at
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dee-BUG-eeng hook
default A particular setting or value for a variable that is assigned automatically by an operating system or a program. It remains in effect unless canceled or overridden by the user. Example:
I changed the default for the font in the word processing program.
The default behavior of the ls command is to display all files and directories, except the dot files .
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See also:
default option, convention
DEE-falt
default behavior The output that is generated when a command with no arguments, is called the default behavior of that command The default behavior of the cp command is to copy over files without asking. More about default behavior at
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DEE-fawlt bee-HAYV-yur
default option An option that is selected automatically unless another one is specified. Example:
...
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default
dee-falt OP-shun
Dennis Ritchie father of C programming language More about Dennis Ritchie at
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DEN-nis RICH-ee
determinate loop “A loop where the number of itmes the loop is run is known before the loop is started.” More about determinate loop at
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dee-TUR-min-ut loop
directory tree Unix uses a hierarchical structure for organizing files and directories. This structure is often referred to as a directory tree. The tree has a single root node, /, and all other directories are contained below it. More about directory tree at
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duh-REK-to-ree TREE
document “Any specific type of file produced or edited by a specific application; usually capable of being printed.” "HTML document"; "Word document"; "Photoshop document" More about document at
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DOCK-yoo-munt
environment variable A variable that is available to any program. More about environment variable at
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See also:
environment
en-VI-run-mnt VAIR-ee-ubl
escape sequence A special sequence of characters that represents another character. ^C More about escape sequence at
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ess-KAPE SEE-kwens
escaping Escaping a character means to put some other character, usually a backslash () just before that character, to change its meaning. Escaping can either remove the special meaning of a character, or add special meaning. The character following the backslash is called an escaped character. ' removes the special meaning of the More about escaping at
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See also:
and indicates that it is just another character.
n gives a special meaning to the n character
indicating that it is means "line feed".'
exclusion set A set of characters that the pattern must not contain. More about exclusion set at
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ecks-KLOO-zhun set
exporting A variable is placed in the environment by exporting it using the export command More about exporting at
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eks-PORT-eeng
expression A command (statement) that returns a value. More about expression at
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ex-PRESH-un
field 1. unix, programming: A set of characters that are separated by one or more field separator characters.
2. database: ...
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See also:
csv, tsv
feeld
field separator Controls the manner in which in input line is broken into fields. In the shell, the field separator is stored in the variable IFS.
In awk the field separator is stored in the awk variable FS. Both the shell and awk use the default values of space and tab for the field separator.
More about field separator at
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FEELD SEP-er-ay-tur
file A stream of bytes treated and stored by the operating system as one thing. Or, more accurately, an element of a filesystem. More about file at
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See also:
computer file
file
file descriptor An integer that is associated with a file. Allow you to read and write from a file with your code, using the integer instead of the filename. More about file descriptor at
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file di-SKRIP-tor
file format “A particular way to encode information for storage in a computer file More about file format at
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FILE for-tum
filter A particular type of unix program that expects to work either with file redirection or as part of a pipeline. These programs read input from standard input, write to standard output, and often don't have any starting arguments. More about filter at
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FIL-tur
function A piece of code in a program that is given a name so that it can be called multiple times. More about function at
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FUNK-shun
Grace Hopper Legendary programmer; discovered the first physical bug in a computer: a moth that got caught in the vacuum tubes. More about Grace Hopper at
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grase HOP-pur
hacker A programmer who enjoys coding and solving problems. More about hacker at
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HACK-ur
hierarchy “An organisation with few things, or one thing, at the top and with several things below each other thing.” The unix filesystem is hierarchical: Each directory may contain files or other directories More about hierarchy at
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HI-ur-ar-kee
inclusion range A range of characters that the pattern must include. More about inclusion range at
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in-KLOO-zhun range
indeterminate loop “A loop where the number of itmes the loop is run is not known before the loop is started.” More about indeterminate loop at
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in-duh-TUR-min-ut loop
infinite loop A loop that executes forever without terminating. More about infinite loop at
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in-fih-nit LOOP
interactive mode In interactive mode, the shell gets input from the user and executes the commands that the user specifies. The shell is interacting with the user. More about interactive mode at
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in-tur-AK-tiv mode
interactive program An application that expects the user to enter information and then responds. The ls command is not interactive, but the more program, which responds to your keypress, is interactive. More about interactive program at
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in-tur-AK-tiv PRO-gram
interface A program or display that gives a human a way to talk to the computer, and the computer a way to talk to the human. interpreter, shell More about interface at
    foldoc.org
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in TUR face
interpreter A program that interprets, or translates, from one thing to another thing. interface, shell More about interpreter at
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in TUR pruh tur
interrupt A signal to a program that tells the program to do something that is not in the usual flow of control. SIG_HUP More about interrupt at
    foldoc.org
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noun: IN-tur-rupt
verb: in-tur-RUPT
iteration A single execution of the body of a loop. More about iteration at
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it-ur-AY-shun
jargon foo More about jargon at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
Eric Raymond
JAR-gun
language A sequence of "tokens" such as words, characters, or other symbols , which is used to communicate. A language has a syntax and vocabulary. More about language at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
program, perl, shell, php, C
LANG-widge
Larry Wall Esteemed programmer/hacker - Inventor of unix patch utility, the perl language, rn network news reader More about Larry Wall at
    foldoc.org
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LARE-ee WALL
left rooted Patterns that must occur at the beginning of a line More about left rooted at
    foldoc.org
    techweb
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    wikipedia
left ROO-ted
library A file used by another program. It usually contains only functions, and not main code. More about library at
    foldoc.org
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LEYE-brair-ee
literal character A character with no special meaning, so which causes no special action to be taken. Quoting causes the shell or program code to treat a wildcard as a literal character. a, 1, X are literal characters.
* usually has special meaning, but if we put it in hard quotes: '*', it will lose its special meaning and merely display as *.
More about literal character at
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LIT-ur-ul KARE-uk-tur
local variable A variable that is present within the current block of code, or within the current instance of the shell. It is not available outside the block, or to programs that are started by that shell. More about local variable at
    foldoc.org
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LO-kul VAIR-ee-ubl
logic reasoning More about logic at
    foldoc.org
    techweb
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    wikipedia
LOJ ik
loop One or more commands that are executed repeatedly (while a condition is true. Enables the program to execute one or a series of commands multiple times. Two main types of loops are the while and for loops. More about loop at
    foldoc.org
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loop
main code All the commands in a program that are not contained within functions. usually contain the main logic of the program. More about main code at
    foldoc.org
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mane code
meta Means, "something about itself". We might have a meeting to discuss where and when to have our meetings. That would be a "meeting about meetings" – a meta-meeting.
Meta-data is information (or data) about data.
More about meta at
    foldoc.org
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MEH-tuh
metacharacter In a regular expression, a metacharacter is a special character that is expanded to match patterns. More about metacharacter at
    foldoc.org
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MET-uh KARE-uk-tur
minimal constraint "The principle of minimal contstraint": The idea that designs (such as engineering or programming designs) should define or lmit only what they have to. They should leave other aspects of the system as unconstrained as possible. More about minimal constraint at
    foldoc.org
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min-ih-mul con-STRAINT
MIT Common abbreviation for Massachusetts Institute of Technology More about MIT at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
em eye tee
modulus function See remainder function More about modulus function at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
MOD-you-lus FUNK-shun
nested loop When a loop is located inside the body of another loop, it is said to be nested within another loop. More about nested loop at
    foldoc.org
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NEST-ed LOOP
newline character Literally, the linefeed character whose ASCII value is 10. In some programming languages, the newline character is a special character that indicates the end of , and that it may now be executed. In unix, the newline character is represented by n, in mswindows by rn, and on macintosh by r More about newline character at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
NOO-line KAR-uk-tur
no-op A command that does nothing, and thus can be used as a dummy command, or placeholder, where syntax requires a command. More about no-op at
    foldoc.org
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no-awp
node A thing that is joined by links. In the web, a node is a web page – or technically, any resource with a URI. More about node at
    foldoc.org
    techweb
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    wikipedia
node
noninteractive mode In noninteractive mode, the shell or operating system does not interact with the user. Rather, it reads commands stored in a file and executes them. When it reaches the end of the file, the shell exits. More about noninteractive mode at
    foldoc.org
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NON-in-tur-AK-tiv MODE
null character Each character in unix has a specific value (in unix only?). Any character with a numeric value of zero (0) is known as a null or null character. More about null character at
    foldoc.org
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null KAR-uk-tur
numeric expression A command used to add, subtract, multiply, and divide two numbers. Numeric expressions are constructed using the numeric operators">. More about numeric expression at
    foldoc.org
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noo-MAIR-ik eks-PRESH-un
numeric operator The symbols used in numeric expressions:
+ (add), - (subtract), * (multiply), / (divide), and % (modulo).
More about numeric operator at
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noo-MAIR-ik OP-ur-ay-tur
object-oriented programming (OOP) A kind of programming which uses the concept of an object, which contains methods. More about object-oriented programming at
    foldoc.org
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pronounce
open source Software whose source code is freely distributed and can by viewed (and modified) by anyone. open source is a trademark of opensource.org. Open Source Software, abbreviated as OSS linux, perl, php, internet More about open source at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
Intellectual Property, FLOSS, Richard Stallman, Larry Wall, Tim O'Reilly
OH-pen SORSE
ordinary file A file on the filesystem that contains data, text, or program instructions. More about ordinary file at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
block special file, character special file
OR-din-air-ee file
output redirection In unix, the process of capturing the output of a command and storing it in a file, sending it to another program (via a pipe), etc. The output is redirected from the default, the screen. More about output redirection at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
OUT-put ree-duh-REK-shun
parent process A process that controls another (referred to as the child process or subprocess). More about parent process at
    foldoc.org
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    wikipedia
PAIR-unt pro-sess
parent process identifier The process identifier of the parent process. More about parent process identifier at
    foldoc.org
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    wikipedia
PAIR-unt pro-sess eye-DEN-tih-feye-ur
parent shell The shell identifier (typically the login shell) that controls another (often referred to as child shell or subshell). More about parent shell at
    foldoc.org
    techweb
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    wikipedia
See also:
parent process
PAIR-unt shell
perl A fourth-generation programming language, developed especially for powerful manipulatiion of strings and files. "the Golden Swiss Army Chainsaw" (cfeaver) Larry Wall More about perl at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
purl
php A fourth-generation programming language, developed especially for the web. More about php at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
pee-aitch-pee
pipeline A series of unix commands chained by | - the pipe character. The output of a command is passed to the next command. ls | wc -l
counts the number of files in the file listing.
echo `who | awk '{print $1}' | sort | uniq` | sed 's/ /,/g'
list the unique names of current users on a single line, separated by commas.
More about pipeline at
    foldoc.org
    techweb
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    wikipedia
pipe-line
piping The process used to redirect the output of one command into the input of another command. Piping in the unix shell is done with the | (pipe) character. More about piping at
    foldoc.org
    techweb
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    wikipedia
PIPE-eeng
process 1. "program": A program that is running. It also could be stopped, sleeping, wedged, or a zombie. In all cases, it is taking up memory, and the attention of the operating system, and it will be shown in the ps command. The user's interactive session is a process. A process can invoke (run) and control another program, that is then referred to as a subprocess. Ultimately, everything a user does is the subprocess of the operating system More about process at
    foldoc.org
    techweb
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    wikipedia
PROH-sess
process identifier The unique number assigned to every process running in the system. Shown in the heading of the ps command as pid. More about process identifier at
    foldoc.org
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    wikipedia
PRO-sess eye-DEN-tih-feye-ur
program One or more commands in a file, written in one of the many programming languages. In the unix shell a program would be run as a command. In a graphical interface (GUI) it would be run by clicking on an icon or select from a menu. On the web it might be run by clicking on a link or typing in a url. More about program at
    foldoc.org
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    wikipedia
PRO-gram
programmer A person who writes code, as programs or scripts. More about programmer at
    foldoc.org
    techweb
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    wikipedia
See also:
coder
PRO-gram-ur
programming Telling a computer what to do, by writing words that it can understand. We call these words "code". They are similar to human language, and are written in a simple text file with a text editor. More about programming at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
PROH-gram-eeng
programming language C, C++, Perl, PHP, shell, ... More about programming language at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
PRO-gram-eeng LANG-wij
protocol "language"; also "rules of behavior". The language and set of rules that define how computers will interact. Examples of protocols are FTP and HTTP. More about protocol at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
PRO-to-kol
quoting Literally, to enclose selected text within some type of quotation marks. In programming, quoting means to use double (") or single (') quotes to tell the programming language whether or not to interpret the values inside the quotes. $this = 'cat';
echo '$this'; -> $this
echo "$this"; -> cat
More about quoting at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
KWO-teeng
recursive command A command that calls, or invokes, itself More about recursive command at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
ree-KUR-siv kum-mand
redirection Most unix programs expect to read their input the from user (standard input and write (send) their output to the screen (standard output). By use of redirection, however, input can come from a previously created file, and output can be saved to a file instead of being displayed on the screen. > and >> are used to redirect the input, output, and error.



$ls -l > filelist.txt
More about redirection at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
file ree-di-REK-shun
regular expression A convenient notation for specifying complex patterns Examples:
^ to match the beginnning of the line
$ to match the end of the line.
More about regular expression at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
REG-you-lar ex-PRESH-un
regular file The most common type of file. Regular files store any kind of data. It may be stored in plain text, an application-specific format, or a special binary format that the system can execute. More about regular file at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
REG-you-lur file
remainder function The remainder of a division operation: the amount that is left over, and not evenly divisible. Also called modulus function The remainder (modulo) of
5 / 2 is 1
More about remainder function at
    foldoc.org
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    wikipedia
ree-MAIN-dur FUNK-shun
reserved word A non-quoted word that is used in grouping commands or selectively executing them. if, then, else, case, for, while, etc. More about reserved word at
    foldoc.org
    techweb
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    wikipedia
ree-ZURVD WORD
scalar A variable that can hold only one value at a time. More about scalar at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
array
skail-ur
script A program which does not need to be compiled before being run., A program written in perl is called a script More about script at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
scripting language, php, shell
skript
scripting language A programming language in which the program does not need to be compiled before being run. shell, perl, php are scripting languages More about scripting language at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
script
SKRIP-ting lang-gwidge
separation of form from content The principle that one should work separately, with the content of a document and with the style in which it is presented. This was an important factor in the decision to use SGML in the web's language, by the web's creator Tim Berners-Lee. More about separation of form from content at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
CSS, style sheet
sep-uh-ray-shun uv FORM frum KON-tent
set group ID "SGID". The SGID permission causes a script or program to run with its group set to the group of the script, rather than the group of the user who started it. More about set group ID at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
set grup eye-dee
set user ID "SUID". The SUID permission causes a script or program to run as the user who is the owner of the script, rather than the user who started it. More about set user ID at
    foldoc.org
    techweb
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set you-zur eye-dee
shebang #!
Programmer's way of saying the two characters # (haSH or SHarp), and ! (bang). Usually used in talking about "the shebang line"
More about shebang at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
en.wikipedia.org/wiki/ Shebang_%28Unix%29
Also called hash-bang
shuh-BANG
shebang line Programmer's way of describing the first line, beginning with shebang (#!), that must appear in a file of code written in an interpreted language on unix. #!/usr/bin/perl More about shebang line at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
en.wikipedia.org/wiki/ Shebang_%28Unix%29
shuh-BANG
signal handler A function that executes when a signal is received by a program. Usually signal handlers clean up temporary files and then exit More about signal handler at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
SIG-nul HAND-ler
simple command A command that you can execute by just giving its name at the prompt More about simple command at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
compound command
SIM-pul kum-mand
standard error A special type of output used for error messages. The file descriptor for STDERR is 2. More about standard error at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
STAN-durd err-or
standard in See standard input More about standard in at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
standard out, standard error
STAN-durd in
STDERR See standard error More about STDERR at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
STDIN, STDOUT
STAN-durd err-or
STDIN See standard input More about STDIN at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
STDERR, STDOUT
STAN-durd in
STDOUT See standard output More about STDOUT at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
STDERR, STDIN
STAN-durd out
string Sequences of various simple objects. Usually these "simple objects" will be printable characters and the control codes that are used with them, but they may also be binary code. string as related to computers, at Wikipedia More about string at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
string
subset More about subset at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
SUB-set
superset More about superset at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
SOO-per-set
syntax The structure of a language: the order of the words, special use of words, etc. In the syntax of the Tibetan language, the verb comes before the subject. In the syntax of the English language, the verb comes after the subject. In the syntax of command line shell, the verb comes first More about syntax at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
SIN-taks
tab separated values The long way to say "tsv" More about tab separated values at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
TAB SEP-ur-ate-ed VAL-yous
text One or more characters Character as related to computers, and plain text, at Wikipedia More about text at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
text
transpose case To switch uppercase letters to lowercase, or lowercase to uppercase ABC -> abc More about transpose case at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
trans-POZ case
tsv "tab separated values" A format for organising data, by separating the fields or values with tabs 'dog'    'cat'    'rat' More about tsv at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
database, csv
tee-ess-vee
value Some kind of data in a variable. More about value at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
VAL-yoo
variable A name for a piece of data. More about variable at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
See also:
constant
VAIR-ee-uh-bul
variable substitution The process of replacing the value of a variable for the variable's name. More about variable substitution at
    foldoc.org
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    wikipedia
VAIR-ee-uh-bul sub-stih-TOO-shun
wildcard A special character that is interpreted to have a meanng other than the character itself. Example:
* is a shell wildcard and creates a pattern that matches zero or more characters.
When prefaced, for example, with the letter dd* – this shell pattern will match all files beginning with d – like this:
ls d*
dog.txt
driving.jpg
dt.doc
More about wildcard at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
WILD-card
zero-length variable A variable that does not have a value assigned to it. More about zero-length variable at
    foldoc.org
    techweb
    dictionary.com
    wikipedia
zee-ro-length VAIR-ee-uh-bul