Perl System Functions 155 codes

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1 A double dash (--) by itself signals the end of the command-line switches
2 A program that generates random integers between 1 and 10
3 Alarm(5)
4 All installed files
5 Behavior of eval
6 Benchmark timethis
7 Call external command
8 Calling system
9 Check if a file exists
10 Combine rand function and letter range to generate random letter
11 Combine unpack and pack in one statement
12 Compare complex number
13 Convert value to degree
14 Converts from degrees to radians
15 Create a big integer
16 Create arsine value
17 Create Complex number
18 Demonstrating some math functions
19 Detecting Whether Your Script Is Running on Windows or UNIX using $^O
20 Displays the current date and time in a Web browser
21 Distinguish between the parent and child processes
22 Encrypt files
23 English name
24 Expired user
25 Extract command-line switches with Getopt
26 File group listing
27 Find all users without passwords
28 For a text string value, use
29 Fork returns the childs process ID
30 Formula to produce random numbers between 5 and 15 inclusive
31 Generate random numbers
32 Generate random passwords
33 Get abbreviations
34 Get group name
35 Get Terminal Size
36 Get the absolute value
37 Get the basename of a file
38 Get the dirname from a file name
39 Get user login names
40 Getgrent function
41 Getopt(pMN)
42 GetOptions(file=s = $file)
43 Getprotoent function
44 If the value is optional, use a colon
45 Is scalar readonly
46 Launching Processes by using Calling exec
47 Let system determine seed
48 List group
49 List users
50 Map function with regular expression
51 Pack and unpack
52 Pack to hex string and unpack
53 Pass new variable name to Data
54 Perform consistent command line parsing
55 Print (4 atan2 1, 1)
56 Print out all users on your UNIX system
57 Print pack(c, 68, 69, 70, 71)
58 Print pack(c3, 65, 66, 67)
59 Print pack(ccc, 88, 89, 90)
60 Print POSIX
61 Process complex command lines
62 Putting Sleep into foreach loop
63 Qualify(scalar)
64 Qualify(scalar,My
65 Qualify_to_ref(scalar,My
66 Quota, change or age
67 Random integers produced by 1 + int( rand( 6 ) )
68 Random numbers produced by rand( 100 )
69 Random numbers produced by rand()
70 Read from a file
71 Read password
72 Read password without displaying anything
73 Read system command and execute
74 Read the password file
75 ReadMode(cbreak)
76 Runs pre-configured test scripts or programs
77 Seed rand with the time or the pid of this process
78 Set new prompt letter for terminal when reading data
79 Setlocale function
80 Shell command
81 Sign a file or message
82 Simple options
83 Soundex function
84 Srand function
85 Stty cbreak devtty 1
86 System stty cbreak devtty &1
87 Test a UNIX password
88 The defined Function
89 The die function exits the Perl script and prints out an error message to STDERR
90 The English Module
91 The eval command executes a snippet of Perl code
92 The getgrnam function retrieves the group file entry corresponding to a particular group name
93 The getpgrp function retrieves the process group ID for a particular process
94 The pack Function Character Codes
95 The pack-format characters, as used by unpack
96 The Perl function getgrent retrieves an item from the user group file
97 The sleep command puts your process to sleep for a number of seconds
98 The system command executes a command and waits until that command completes
99 The Template pack and unpack Types and Values
100 The undef Function
101 The wait function
102 The waitpid function
103 To display all the etcpasswd fields for users passed on the command line
104 To exit a Perl script, use the die function or the exit function
105 To retrieve the process ID for the parent process for your program, call the function getppid
106 To turn a feature on or off Use the exclamation point(!)
107 Use Benchmark to time a loop
108 Use Class
109 Use Cwd
110 Use Data
111 Use Data Dumper to dump the reference
112 Use English
113 Use Env
114 Use Env qw(PATH HOME)
115 Use File
116 Use Math
117 Use Safe
118 Use Term
119 Use Text
120 Use the Data
121 Use Time
122 Use User
123 Uses the system function to clear the screen
124 Using acos function
125 Using cos function
126 Using Data
127 Using die to ouput error message
128 Using eval to evaluate an expression
129 Using eval to test whether a function is implemented
130 Using exec to launch the windows program
131 Using exit command to exit an program
132 Using exp function
133 Using foreach loop to create a list of random number
134 Using fork and pipe
135 Using fork to create child processes
136 Using function die to terminate a program
137 Using Getopt to deal with command line options
138 Using Map function
139 Using pack and unpack to convert decimal number to binary number back and forth
140 Using PI constant
141 Using rad2deg to convert radian to degree
142 Using scalar function to convert array to scalar variable
143 Using scalar() function to interpret an array variable in scalar context to get its length
144 Using sin function
145 Using sin function with radian
146 Using system on Windows
147 Using system on Windows with the Windows START command
148 Using system to call a command passed in by an array
149 Using system to call osshell function
150 Using tan function
151 Using vec
152 Using waitpid
153 Values Returned by getpwnam
154 Waiting for child processes to exit
155 Waitpid waits for a particular child process to complete, returning 1 if the process is found and -1 on an error