Functions for SCALARs or strings
    chomp, chop, chr, crypt, hex, index, lc, lcfirst,
    length, oct, ord, pack, q/STRING/, qq/STRING/,
    reverse, rindex, sprintf, substr, tr///, uc, ucfirst,
    y///

Regular expressions and pattern matching
    m//, pos, quotemeta, s///, split, study

Numeric functions
    abs, atan2, cos, exp, hex, int, log, oct, rand, sin,
    sqrt, srand

Functions for real @ARRAYs
    pop, push, shift, splice, unshift

Functions for list data
    grep, join, map, qw/STRING/, reverse, sort, unpack

Functions for real %HASHes
    delete, each, exists, keys, values

Input and output functions
    binmode, close, closedir, dbmclose, dbmopen, die,
    eof, fileno, flock, format, getc, print, printf,
    read, readdir, rewinddir, seek, seekdir, select,
    syscall, sysread, syswrite, tell, telldir, truncate,
    warn, write

Functions for fixed length data or records
    pack, read, syscall, sysread, syswrite, unpack, vec

Functions for filehandles, files, or directories
    -X, chdir, chmod, chown, chroot, fcntl, glob, ioctl,
    link, lstat, mkdir, open, opendir, readlink, rename,
    rmdir, stat, symlink, umask, unlink, utime

Keywords related to the control flow of your perl program
    caller, continue, die, do, dump, eval, exit, goto,
    last, next, redo, return, sub, wantarray

Keywords related to scoping
    caller, import, local, my, package, use

Miscellaneous functions
    defined, dump, eval, formline, local, my, reset,
    scalar, undef, wantarray

Functions for processes and process groups
    alarm, exec, fork, getpgrp, getppid, getpriority,
    kill, pipe, qx/STRING/, setpgrp, setpriority, sleep,
    system, times, wait, waitpid

Keywords related to perl modules
    do, import, no, package, require, use

Keywords related to classes and object-orientedness
    bless, dbmclose, dbmopen, package, ref, tie, tied,
    untie, use

Low-level socket functions
    accept, bind, connect, getpeername, getsockname,
    getsockopt, listen, recv, send, setsockopt, shutdown,
    socket, socketpair

System V interprocess communication functions
    msgctl, msgget, msgrcv, msgsnd, semctl, semget,
    semop, shmctl, shmget, shmread, shmwrite

Fetching user and group info
    endgrent, endhostent, endnetent, endpwent, getgrent,
    getgrgid, getgrnam, getlogin, getpwent, getpwnam,
    getpwuid, setgrent, setpwent

Fetching network info
    endprotoent, endservent, gethostbyaddr,
    gethostbyname, gethostent, getnetbyaddr,
    getnetbyname, getnetent, getprotobyname,
    getprotobynumber, getprotoent, getservbyname,
    getservbyport, getservent, sethostent, setnetent,
    setprotoent, setservent

Time-related functions
    gmtime, localtime, time, times

Functions new in perl5
    abs, bless, chomp, chr, exists, formline, glob,
    import, lc, lcfirst, map, my, no, qx, qw, ref, sub*,
    sysopen, tie, tied, uc, ucfirst, untie, use

    * - sub was a keyword in perl4, but in perl5 it is an
    operator which can be used in expressions.

Functions obsoleted in perl5
    dbmclose, dbmopen