-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
bind: binds an address to a socket
binmode: prepare binary files on old systems
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 remove 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 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 all
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 hend 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
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
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
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
readlink: determine where a symbolic link is pointing
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 sin 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
sysread: fixed-length unbuffered input from a filehandle
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
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 list vs array context of current subroutine call
warn: print debugging info
write: print a picture record
y///: transliterate a string