UNIX COMMANDS - 2

Network Utilities

1. who

NAME
who - show who is logged on
SYNOPSIS
who [OPTION]... [ FILE | ARG1 ARG2 ]
DESCRIPTION
-a, --all
same as -b -d --login -p -r -t -T -u
-l, --login
print system login processes
2. w

NAME
w - Show who is logged on and what they are doing.

SYNOPSIS
w - [husfV] [user]

DESCRIPTION
w displays information about the users currently on the machine, and their processes.


3. finger

NAME
finger - user information lookup program

SYNOPSIS
finger [-lmsp] [user ...] [user@host ...]

DESCRIPTION
The finger displays information about the system users.

4. whoami

NAME
whoami - print effective userid

SYNOPSIS
whoami [OPTION]...

DESCRIPTION
Print the user name associated with the current effective user ID. Same as id -un.

--help display this help and exit
--version
output version information and exit

5. ftp

NAME
ftp - Internet file transfer program

SYNOPSIS
ftp [-pinegvd] [host]
pftp [-inegvd] [host]

DESCRIPTION
Ftp is the user interface to the Internet standard File Transfer Protocol.


6. telnet

NAME
telnet - user interface to the TELNET protocol

SYNOPSIS
telnet [-8EFKLacdfrx] [-X authtype] [-b hostalias] [-e escapechar] [-k realm] [-l user] [-n tracefile] [host [port]]

DESCRIPTION
The telnet command is used to communicate with another host using the TELNET protocol.


7. rlogin

NAME
rlogin - remote login

SYNOPSIS
rlogin [-8EKLdx] [-e char] [-l username] host

DESCRIPTION
Rlogin starts a terminal session on a remote host host.

Text Processing Utilities

1. cat

with redirection operators.
eg:
[prasad@localhost ~]$ cat prasad.txt > com.txt
[prasad@localhost ~]$ cat com.txt
prasad
prasad

2. head

NAME
head - output the first part of files

SYNOPSIS
head [OPTION]... [FILE]...

DESCRIPTION
Print the first 10 lines of each FILE to standard output.

-n, --lines=[-]N
print the first N lines instead of the first 10; with the leading ‘-’, print all but the last N lines of each file

-q, --quiet, --silent
never print headers giving file names

-v, --verbose
always print headers giving file names

3. tail

NAME
tail - output the last part of files

SYNOPSIS
tail [OPTION]... [FILE]...

DESCRIPTION
Print the last 10 lines of each FILE to standard output.

-q, --quiet, --silent
never output headers giving file names

-s, --sleep-interval=S
with -f, sleep for approximately S seconds (default 1.0) between iterations.

-v, --verbose
always output headers giving file names

4. uniq

NAME
uniq - report or omit repeated lines

SYNOPSIS
uniq [OPTION]... [INPUT [OUTPUT]]

DESCRIPTION
Discard all but one of successive identical lines from INPUT (or standard input), writing to OUTPUT (or standard output).

-i, --ignore-case
ignore differences in case when comparing

5. cut

NAME
cut - remove sections from each line of files

SYNOPSIS
cut [OPTION]... [FILE]...

DESCRIPTION
Print selected parts of lines from each FILE to standard output.

-b, --bytes=LIST
select only these bytes

-c, --characters=LIST
select only these characters

6.join

NAME
join - join lines of two files on a common field

SYNOPSIS
join [OPTION]... FILE1 FILE2

DESCRIPTION
For each pair of input lines with identical join fields, write a line to standard output. The default join field is the first, delim-
ited by whitespace.

-e EMPTY
replace missing input fields with EMPTY

-i, --ignore-case
ignore differences in case when comparing fields

7. paste

NAME
paste - merge lines of files

SYNOPSIS
paste [OPTION]... [FILE]...

DESCRIPTION
Write lines consisting of the sequentially corresponding lines from each FILE, separated by TABs, to standard output.

-d, --delimiters=LIST
reuse characters from LIST instead of TABs

-s, --serial
paste one file at a time instead of in parallel

8. comm

NAME
comm - compare two sorted files line by line

SYNOPSIS
comm [OPTION]... FILE1 FILE2

DESCRIPTION
Compare sorted files FILE1 and FILE2 line by line.

-1 suppress lines unique to FILE1

-2 suppress lines unique to FILE2

-3 suppress lines that appear in both files

9. cmp

NAME
cmp - compare two files

SYNOPSIS
cmp [-l | -s] file1 file2 [skip1 [skip2]]

DESCRIPTION
The cmp utility compares two files of any type and writes the results to the standard output. By default, cmp is silent if the files
are the same; if they differ, the byte and line number at which the first difference occurred is reported.

-l Print the byte number (decimal) and the differing byte values (octal) for each difference.

-s Print nothing for differing files; return exit status only.


10. nl

NAME
nl - number lines of files

SYNOPSIS
nl [OPTION]... [FILE]...

DESCRIPTION
Write each FILE to standard output, with line numbers added.

11. wc

NAME
wc - print newline, word, and byte counts for each file

SYNOPSIS
wc [OPTION]... [FILE]...
wc [OPTION]... --files0-from=F

DESCRIPTION
Print newline, word, and byte counts for each FILE, and a total line if more than one FILE is specified.

-c, --bytes
print the byte counts

-l, --lines
print the newline counts

-w, --words
print the word counts

12. tr

NAME
tr - translate or delete characters

SYNOPSIS
tr [OPTION]... SET1 [SET2]

DESCRIPTION
Translate, squeeze, and/or delete characters from standard input, writing to standard output.

-c, -C, --complement
first complement SET1

-d, --delete
delete characters in SET1, do not translate

13. grep

NAME
grep, egrep, fgrep - print lines matching a pattern

SYNOPSIS
grep [options] PATTERN [FILE...]
grep [options] [-e PATTERN | -f FILE] [FILE...]

DESCRIPTION
Grep searches the named input FILEs (or standard input if no files are named, or the file name - is given) for lines containing a
match to the given PATTERN. By default, grep prints the matching lines.

-a, --text
Process a binary file as if it were text; this is equivalent to the --binary-files=text option.

14. tee

NAME
tee
- read from standard input and write to standard output and files

SYNOPSIS
tee [OPTION]... [FILE]...

DESCRIPTION
Copy standard input to each FILE, and also to standard output.

-a, --append
append to the given FILEs, do not overwrite

-i, --ignore-interrupts
ignore interrupt signals