LINUX COMMANDS

write user [tty]
message

Initiate or respond to an interactive conversation with user. A write session is terminated with EOF. If the user is logged into more than
one terminal, specify a tty number. See also talk; use mesg to keep other users from writing to your terminal.

wodim [options] track1,track2...

Record data or audio CD or DVD media. This program normally requires root access to the device file; run as root or install suidroot.
It has a large number of options and settings; see the manpage for a complete list as well as a number of useful examples.

whois[options] query[@server[:port]]
jwhois [options] query[@server[:port]]

Search a whois database for a domain name, IP address, or NIC name. The information returned varies, but usually contains administrative and technical contacts so that you can find a person to handle problems at that domain. By default, the command
returns information on .com, .net, and .edu domains, but other hosts can be queried for other domains using host or the -h option.

whoami

Print current user ID. Equivalent to id -un

who [options] [file]
who am i

Show who is logged into the system. With no options, list the names of users currently logged in, their terminal, the time they
have been logged in, and the name of the host from which they have logged in. An optional system file (default is /etc/utmp) can be
supplied to give additional information.

which [options] [--] [commands]

List the full pathnames of the files that would be executed if the named commands had been run. which searches the user’s $PATH
environment variable.

whereis [options] files

Locate the binary, source, and manual page files for specified commands/files. The supplied filenames are first stripped of leading pathname components and any (single) trailing extension of the form .ext (for example, .c). Prefixes of s. resulting from use of
source code control are also dealt with. whereis then attempts to locate the desired program in a list of standard Linux directories (/bin, /etc, /usr/bin, /usr/local/bin/, etc.).

whatis keywords

Search the short manual page descriptions in the whatis database for each keyword and print a one-line description to standard
output for each match. Like apropos, except that it searches only for complete words. Equivalent to man -f.

wget [options] [urls]

Perform noninteractive file downloads from the Web. wget works in the background and can be used to set up and run a download
without the user having to remain logged on. wget supports HTTP, HTTPS, and FTP, as well as downloads through HTTP proxies. wget uses a global startup file that you may find at /etc/wgetrc or /usr/local/etc/wgetrc. In addition, users can define their own  $HOME/.wgetrc files.

wc [options] [files]

Print byte, word, and line counts for each file. Print a total line for multiple files. If files is omitted or is -, read standard input. See other examples under ls and sort.