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C Shell $argv Notation

Notation Description
$#argv Count the number of command-line arguments.
$* Display all arguments.
$argv Display all arguments.
$argv [1-3] Display arguments 1 through 3.
$0 Display the command used to run the shell script.
$argv [n] Display the nth argument.
$argv [$#argv} Display the last argument.


Character Term Description
\ Backslash Nullifies the special meaning of the following shellmetacharacter, including another backslash.
`` Backquotes The output is substituted as if it were typed in place of thecommand. Refer to the shell manual pages for more information.
'' Single quote Nullifies the special meaning of all characters except bang(!), the backslash (\), and the single quote itself ('). Singlequotes are more restrictive than double quotes and do not permitvariable or backquote expansion.
"" Double quotes Nullifies the special meaning of all special characters exceptbang (!), backquote (``), and dollar sign ($). Permits variable andbackquote expansion.

Metacharacter Shell Syntax

Feature Bourne and Korn C
Single-character wildcard ? ?
Any number of characters * *
Set of single characters [abc] [abc]
Range of single characters [a-c] [a-c]
Inverse range of single characters [!a-c] N/A

Variable Shell Syntax

Feature Bourne Korn C
Assigning regular variables x=1 x=1 set x = 1
Accessing regular variables echo $x echo $x echo $x
Assigning arrays N/A y[0]=1; y[1]=2 set y=(1 2)
Accessing array elements N/A echo $y echo $y[1] $y[2]
echo ${y[1]}
Accessing entire array N/A echo ${y[*]} echo $y
Exporting variables (make global) export var export var use setenv command
Command-line arguments N/A N/A $argv, $#argv, $argv[1}
Positional parameters $*, $#, $1 $*, $#, $1 $*, $1
Setting positional parameters set a b c set a b c N/A

I/O Redirection and Piping

Feature Bourne Korn C
STDOUT to file >filenameor 1>filename >filenameor 1>filename >filename
STDIN from file <filenameor 0<filename <filenameor 0<filename <filename
STDERR to file 2>filename 2>filename N/A
Output and errors to file 2>&1 2>&1 >&filename
Output to next command | cmd | cmd | cmd
Output and errors to next command 2>&1 | 2>&1 | |&

Printing to the Screen

Feature Bourne Korn C
Display text and variables echo print or echo echo

Reading from the Keyboard

Feature Bourne Korn C
Read keyboard input readname1name2. . . readname1name2. . . set var = $<

Math and Calculations

Feature Bourne Korn C
Perform a calculation var=`expr a + b` let var= a + b @ var = (a + b)
Test a relational condition var=`expr a < b` let var=a < b @ var = (a < b)

Command Substitution

Feature Bourne Korn C
Command substitution `command` $(command) or`command` `command`

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