Perl 简明教程

abs - absolute value function

accept - accept an incoming socket connect

alarm - schedule a SIGALRM

atan2 - arctangent of Y/X in the range -PI to PI

bind - binds an address to a socket

binmode - prepare binary files for I/O

bless - create an object

caller - get context of the current subroutine call

chdir - change your current working directory

chmod - changes the permissions on a list of files

chomp - remove a trailing record separator from a string

chop - remove the last character from a string

chown - change the owership on a list of files

chr - get character this number represents

chroot - make directory new root for path lookups

close - close file (or pipe or socket) handle

closedir - close directory handle

connect - connect to a remote socket

continue - optional trailing block in a while or foreach

cos - cosine function

crypt - one-way passwd-style encryption

dbmclose - breaks binding on a tied dbm file

dbmopen - create binding on a tied dbm file

defined - test whether a value, variable, or function is defined or not

delete - deletes a value from a hash

die - raise an exception or bail out

do - turn a BLOCK into a TERM

dump - create an immediate core dump

each - retrieve the next key/value pair from a hash

endgrent - be done using group file

endhostent - be done using hosts file

endnetent - be done using networks file

endprotoent - be done using protocols file

endpwent - be done using passwd file

endservent - be done using services file

eof - test a filehandle for its end

eval - catch exceptions or compile and run code

exec - abandon this program to run another

exists - test whether a hash key is present

exit - terminate this program

exp - raise I to a power

fcntl - file control system call

fileno - return file descriptor from filehandle

flock - lock an entire file with an advisory lock

fork - create a new process just like this one

format - declare a picture format with use by the write() function

formline - internal function used for formats

getc - get the next character from the filehandle

getgrent - get next group record

getgrgid - get group record given group user ID

getgrnam - get group record given group name

gethostbyaddr - get host record given its address

gethostbyname - get host record given name

gethostent - get next hosts record

getlogin - return who logged in at this tty

getnetbyaddr - get network record given its address

getnetbyname - get networks record given name

getnetent - get next networks record

getpeername - find the other end of a socket connection

getpgrp - get process group

getppid - get parent process ID

getpriority - get current nice value

getprotobyname - get protocol record given name

getprotobynumber - get protocol record numeric protocol

getprotoent - get next protocols record

getpwent - get next passwd record

getpwnam - get passwd record given user login name

getpwuid - get passwd record given user ID

getservbyname - get services record given its name

getservbyport - get services record given numeric port

getservent - get next services record

getsockname - retrieve the sockaddr for a given socket

getsockopt - get socket options on a given socket

glob - expand filenames using wildcards

gmtime - convert UNIX time into record or string using Greenwich time format.

goto - create spaghetti code

grep - locate elements in a list test true against a given criterion

hex - convert a string to a hexadecimal number

import - patch a module’s namespace into your own

index - find a substring within a string

int - get the integer portion of a number

ioctl - system-dependent device control system call

join - join a list into a string using a separator

keys - retrieve list of indices from a hash

kill - send a signal to a process or process group

last - exit a block prematurely

lc - return lower-case version of a string

lcfirst - return a string with just the next letter in lower case

length - return the number of bytes in a string

link - create a hard link in the filesytem

listen - register your socket as a server

local - create a temporary value for a global variable (dynamic scoping)

localtime - convert UNIX time into record or string using local time

lock - get a thread lock on a variable, subroutine, or method

log - retrieve the natural logarithm for a number

lstat - stat a symbolic link

m - match a string with a regular expression pattern

map - apply a change to a list to get back a new list with the changes

mkdir - create a directory

msgctl - SysV IPC message control operations

msgget - get SysV IPC message queue

msgrcv - receive a SysV IPC message from a message queue

msgsnd - send a SysV IPC message to a message queue

my - declare and assign a local variable (lexical scoping)

next - iterate a block prematurely

no - unimport some module symbols or semantics at compile time

oct - convert a string to an octal number

open - open a file, pipe, or descriptor

opendir - open a directory

ord - find a character’s numeric representation

our - declare and assign a package variable (lexical scoping)

pack - convert a list into a binary representation

package - declare a separate global namespace

pipe - open a pair of connected filehandles

pop - remove the last element from an array and return it

pos - find or set the offset for the last/next m//g search

print - output a list to a filehandle

printf - output a formatted list to a filehandle

prototype - get the prototype (if any) of a subroutine

push - append one or more elements to an array

q - singly quote a string

qq - doubly quote a string

qr - Compile pattern

quotemeta - quote regular expression magic characters

qw - quote a list of words

qx - backquote quote a string

rand - retrieve the next pseudorandom number

read - fixed-length buffered input from a filehandle

readdir - get a directory from a directory handle

readline - fetch a record from a file

readlink - determine where a symbolic link is pointing

readpipe - execute a system command and collect standard output

recv - receive a message over a Socket

redo - start this loop iteration over again

ref - find out the type of thing being referenced

rename - change a filename

require - load in external functions from a library at runtime

reset - clear all variables of a given name

return - get out of a function early

reverse - flip a string or a list

rewinddir - reset directory handle

rindex - right-to-left substring search

rmdir - remove a directory

s - replace a pattern with a string

scalar - force a scalar context

seek - reposition file pointer for random-access I/O

seekdir - reposition directory pointer

select - reset default output or do I/O multiplexing

semctl - SysV semaphore control operations

semget - get set of SysV semaphores

semop - SysV semaphore operations

send - send a message over a socket

setgrent - prepare group file for use

sethostent - prepare hosts file for use

setnetent - prepare networks file for use

setpgrp - set the process group of a process

setpriority - set a process’s nice value

setprotoent - prepare protocols file for use

setpwent - prepare passwd file for use

setservent - prepare services file for use

setsockopt - set some socket options

shift - remove the first element of an array, and return it

shmctl - SysV shared memory operations

shmget - get SysV shared memory segment identifier

shmread - read SysV shared memory

shmwrite - write SysV shared memory

shutdown - close down just half of a socket connection

sin - return the sine of a number

sleep - block for some number of seconds

socket - create a socket

socketpair - create a pair of sockets

sort - sort a list of values

splice - add or remove elements anywhere in an array

split - split up a string using a regexp delimiter

sprintf - formatted print into a string

sqrt - square root function

srand - seed the random number generator

stat - get a file’s status information

study - optimize input data for repeated searches

sub - declare a subroutine, possibly anonymously

substr - get or alter a portion of a stirng

symlink - create a symbolic link to a file

syscall - execute an arbitrary system call

sysopen - open a file, pipe, or descriptor

sysread - fixed-length unbuffered input from a filehandle

sysseek - position I/O pointer on handle used with sysread and syswrite

system - run a separate program

syswrite - fixed-length unbuffered output to a filehandle

tell - get current seekpointer on a filehandle

telldir - get current seekpointer on a directory handle

tie - bind a variable to an object class

tied - get a reference to the object underlying a tied variable

time - return number of seconds since 1970

times - return elapsed time for self and child processes

tr - transliterate a string

truncate - shorten a file

uc - return upper-case version of a string

ucfirst - return a string with just the next letter in upper case

umask - set file creation mode mask

undef - remove a variable or function definition

unlink - remove one link to a file

unpack - convert binary structure into normal perl variables

unshift - prepend more elements to the beginning of a list

untie - break a tie binding to a variable

use - load in a module at compile time

utime - set a file’s last access and modify times

values - return a list of the values in a hash

vec - test or set particular bits in a string

wait - wait for any child process to die

waitpid - wait for a particular child process to die

wantarray - get void vs scalar vs list context of current subroutine call

warn - print debugging info

write - print a picture record

-X - a file test (-r, -x, etc)

y - transliterate a string