-X

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

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

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 e 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

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/STRING/

  singly quote a string

qq/STRING/

  doubly quote a string

qr/STRING/

  Compile pattern

quotemeta

  quote regular expression magic characters

qw/STRING/

  quote a list of words

qx/STRING/

  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

y///

  transliterate a string