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UNIX is an operating system that support multi-user and multi-tasking in a time sharing environment. Unix OS is used for both server and workstation.
Kernel is the name of Operating System in UNIX. It is the kernel Job to keep each process and user separate and to regulate to access the system hardware
\"mkdir\" command is use to create directory.
Syntax- mkdir [option] <directory name>
Common option
-p create parent directory
-m access permission
Ex- % mkdir /home/frank/data
Or if your present working directory is /home/frank then
% mkdir data
Directory navigation controls are those, which are performed on directories.
For ex-
ls- It show the list of directories
cd- It is used to change directory
mkdir- It is used to create new directory
rmdir- It is used to remove directory
pwd- it is used to show the path of current directory, where the user is exists.
User programs interact with kernel through set of standard system calls. These system calls provide requested service by kernel. Services like open, close, read, write or execute file and changing accessibilityof file and enable access of hardware devices.
UNIX was developed by a group of AT&T employee at Bell Labs, including Ken Thompson, Dennis Ritchie, Douglas Macllroy, Rudd Canaday and Tom Blakeley in 1969.
An inode is special file designed to be read by kernel to learn the information about each file. It specifies the permissions on file, ownership, date of creation and of last access, and change and the physical location of data block on the disk containing the file.
Command is a program that tells the UNIX system to do something. It has the form:
command [options][arguments]
Where an argument indicates on what command is to perform actions, usually a file or set of files. An option modifies the command and changing the way it perform.
Option are generally precede by hyphen (-), and for most commands,more than one option can be stung together, in the form :
command -[option][option][option]
In UNIX system, external commands resides in computer disks.
For example
/bin/ls is an external command.
On other hand, internal command are built into the shell program.
For example
exit is an internal command.
At any time user can determine where he is in file system hierarchy with pwd command, (present working directory).
For ex- % pwd
Output- /home/frank/src
\'cd\' command is basically used for change directory.
The various use of \"cd\" command are:
cd (also chdir in some shells) --> change directory
cd/ -->changes directory to the system\'s root
cd.. -->goes up one directory level
cd../.. -->goes up two directory levels
cd /full/path/name/from/root --> changes directory to absolute path named (note the leading slash)
cd path/from/current/location --> changes directory to path relative to current location (no leading slash)
cd ~username/directory --> changes directory to the named username\'s indicated directory
rmdir command is use to remove directory. It is compulsory that the directory needs to be empty before remove it and if it is also not present working directory,then you must first change of it.
Syntax:
rmdir <directory>
Example- To remove the empty directory /home/frank/data while in /home/frank use:
% rmdir data
Or
% rmdir /home/frank/data
ls command is used to list all directories and files. With option it can provide information about size, type of file, permissions, date of file creation and change and access.
Syntax :ls [options][arguments]
Option
-a list all files including directories those beginning with dot(.)
-d list only name of directory not the files in directory
-al long listing
UNIX vs DOS Navigation & Directory Control Commands
Commands UNIX DOS
List directory ls dir
Make directory mkdir md &mkdir
Change directory cd cd & chdir
Remove directory rmdir rd & rmdir
Return to user\'s home directory cd cd/
location in path pwd cd
(present working directory)
File maintenance commands are to create copy, remove & change permission on files.
You can use the following commands
Commands/syntax working of it.
chgrp [options] group file change the group of file
chmod [options] file change the access mode of file
chown [options] owner file change the ownership of file(only super user can do it)
cp [options] file1 file2 copy the content of file1 into file 2
mv [options] file1 file2 move file1 into file2
rm [options] file remove file or directory
Commands UNIX DOS
copy file cp copy
move file mv move
rename file mv rename & ren
delete file rm erase & del
display file to screen
entire file cat type
one page at a time more.less.pg type/p
You can copy content of a file into another file by using \'cp\' command.
Syntax- cp [options] <old file name> <new file name>
Common option
-i prompt and wait for confirmation before proceeding
-r recursively copy a file
Example- % cp <old file name> <new file name>
Now you have two copies of the file. They are completely independent of each other.
They each have their own inode, data blocks, and directory table entries.
You can rename or move file with mv command.
Syntax-
mv [options] [old filename] [new filename]
Common Options
-i interactive (prompt and wait for confirmation before proceeding)
-f don\'t prompt, even when copying over an existing target file (overrides -i)
Examples
% mv <old filename> <new filename>
Now you have a file called <new filename> and the file <old filename> is gone or deleted.
The contents of the file remain where they were
You can remove a file with the rm command.
Syntax
rm [options] filename
Common Options
-i interactive (prompt and wait for confirmation before proceeding)
-r recursively remove a directory, first removing the files and subdirectories beneath it
-f don\'t prompt for confirmation (overrides -i)
Examples
% rm <filename>
Each file, directory, and executable has permissions set for who can read, write, and/or execute it.
To find the permissions assigned to a file, the ls command with the -l option should be used.
.
For examples-
-rwxr-x--- allows the user (owner) of the file to read, write, and execute it; those in the unixgroup of the file can read and execute it; others cannot access it at all.
To change permissions on file or directory is chmod (change mode). The syntax involves using the command with three digits (representing the user (owner, u) permissions, the group (g) permissions, and other (o) user\'s permissions)Or by using symbolic representation.
Each of the permission types is represented by either a numeric equivalent:
read=4, write=2, execute=1
or a single letter:
read=r, write=w, execute=x
A permission of 4 or r would specify read permissions. If the permissions desired are read and write,the 4 (read) and the 2 (write) are added together to make a permission of 6.Therefore, a permission setting of 6 would allow read and write permissions.
Alternatively, you could use symbolic notation which uses the one letter representation for who and for the permissions and an operator, where the
operator can be:
+ add permissions
- remove permissions
= set permissions
So to set read and write for the owner we could use \"u=rw\" in symbolic notation.
Syntax
chmod nnn [argument list] numeric mode
chmod [who]op[perm] [argument list] symbolic mode
where nnn are the three numbers representing user, group, and other permissions, who is any of u, g,
o, or a (all) and perm is any of r, w, x.
Common Options
-f force (no error message is generated if the change is unsuccessful)
-R recursively descend through the directory structure and change the modes
Examples
If the permission desired for file1 is user: read, write, execute, group: read, execute, other: read,execute, the command to use would be
chmod 755 file1 or chmod u=rwx,go=rx file1
Ownership of a file can be changed with the chown command.It can only be done by the super-user
Syntax
chown [options] user[:group] file
chown [options] user[.group] file
Common Options
-R recursively descend through the directory structure
-f force, and don\'t report any errors
Examples
# chown new_owner file
# represents the shell prompt for the super-user
Anyone can change the group of files they own, to another group they belong to, with the chgrp command.
Syntax:
chgrp [options] group file
Common Options
-R recursively descend through the directory structure
-f force, and don\'t report any errors
Examples
% chgrp new group file
Display command are used to display or view content of file. Some display commands are as follows:
Commands What it will do
cat [options] file concatenate (list) a file
echo [text string] echo the text string to standard output(monitor)
head [number] file display the first 10 (or number of) lines of a file
more (or less or pg) [options] file page through a text file
tail [options] file display the last few lines (or parts) of a file
The cat command is use to display the content of a file
Syntax--
cat [options] [file]
Common Options
-n precede each line with a line number
-v display non-printing characters, except tabs, new-lines, and form-feeds
-e display $ at the end of each line
Examples
% cat filename
You can list a series of files on the command line, and cat will concatenate them, starting each in turn,
immediately after completing the previous one, e.g.:
% cat file1 file2 file3
The echo command is used to repeat the argument you give it back to the standard output device. It normally ends with a line-feed, but you can specify an option to prevent this.
Syntax
echo [option] [string]
Examples
% echo Hello Class or echo \"Hello Class\"
more, less, and pg command let you page through the contents of a file one screen at a time.
These may not all available on your UNIX system.
Syntax
more [options] [+/pattern] [filename]
less [options] [+/pattern] [filename]
pg [options] [+/pattern] [filename]
Internal Controls
more displays (one screen at a time) the file requested
<space bar> to view next screen
<return> or <CR> to view one more line
q to quit viewing the file
h help
b go back up one screen
/word search for word in the remainder of the file
less similar to more
pg equivalent of more
Head command displays the head or start of the file.
Syntax:
head [options] file
Common Options
-n number number of lines to display, counting from the top of the file
-number same as above
Examples
By default head displays the first 10 lines.
You can display more with the \"-n number\", or \"-number\" options, e.g., to display the first 40 lines: % head -40 filename or head -n 40 filename
Tail command displays the tail or end of the file.
Syntax
tail [options] file
Common Options
-number number of lines to display, counting from the bottom of the file
Example
The default is to display the last 10 lines, but you can specify different line or byte numbers, or a different starting point within the file.
To display the last 30 lines of a file use the -number style:% tail -30 filename
The commands that report or manage system resources are known as system resource commands. Some are as follows:
Command/Syntax What it will do
chsh (passwd -e/-s) change the user\\s login shell (only by the super user)
date [options] report the current date and time
df [options] [resource] report the summary of disk blocks and inode free and in use
du [options] [directory or file] report amount of disk space in use+
Hostname/uname display or set (super-user only) the name of the current machine
kill [options] [-SIGNAL] [pid#] [%job] send a signal to the process with the process id number (pid#)
Or job control number (%n).
The default signal is to kill the process.
man [options] command show the manual (man) page for a command
passwd [options] set or change your password
ps [options] show status of active processes
script file saves everything that appears on the screen to file until exit is executed
stty [options] set or display terminal control options
which command reports the path to the command or the shell alias in use
who or w report who is logged in and what processes are running
Date command displays the current data and time. A super user can set the date and time.
Syntax
date [options] [+format]
Common Options
-u Universal Time (or Greenwich Mean Time)
+format specify the output format
%a weekday, Sun to Sat
%h month abbreviation, Jan to Dec
%j day of year, 001 to 366
%n <new-line>
%t <TAB>
%y last 2 digits of year, 00 to 99
%D MM/DD/YY date
%H hour, 00 to 23
%M minute, 00 to 59
%S second, 00 to 59
%T HH:MM:SS time
Example
date
Mon Jun 10 09:01:05 EDT 1996
date -u
Mon Jun 10 13:01:33 GMT 1996
date +%a%t%D
Mon 06/10/96
date \'+%y:%j\'
96:162
Hostname reports the host name of the machine the user is logged into.
Example:
brigadier: condron [91]> hostname
outpu--> brigadier
uname has additional options to print information about system hardware type and software version.
df command is used to report the number of disk blocks and indexes used and free for each file system.
Syntax
df [options] [resource]
Common Options
-l local file systems only
-k report in kilobytes
du command reports the amount of disk space in use for the files or directories.
Syntax:
du [options] [directory or file]
Common Options
-a display disk usage for each file
-s display a summary (total only)
-k report in kilobytes
ps command is used to show status of all processes currently running on the system.
Syntax
ps [options]
kill command is use to terminate a process.
Syntax
kill [-signal] process-id
Common Options
-l displays the available kill signals:
Example
(UNIX prompt) kill -9 15599
who command reports who is logged in that present time.
Syntax:who
which command will report the name of the file that is be executed when the command is invoked. This will be the full path name or the alias that\'s found first in your path.
Syntax:
which command(s)
Example:
UNIX prompt> which MailOutput-- /usr/ucb/Mail
whereis command reports the filenames of source, binary, and manual page files associated with command.
Syntax:
whereis [options] command(s)
Common Options:
-b report binary files only
-m report manual sections only
-s report source files only
script command creates a script of your session input and output. By using the script command,
you can capture all the data transmission from and to your terminal screen until you exit the script program.
Syntax
script [-a] [file] <. . .> exit
Common Options
-a append the output to file typescript is the name of the default file used by script.
You must remember to type exit to end your script session and close your typescript file.
passwd command is use to set or change password. When you enter a password, the string is encrypted by the system.
This encryption stored in a file named shadow in the /etc directory.
Syntax
<prompt>passwd
(current) UNIX password : ******
New UNIX password : ******
Retype UNIX password : ******
User should know his terminal name by using tty (teletype) command. This command is simple and needs no argument.
Syntax
(Unix Prompt) tty
Output
/div/term/2
The terminal file name is 2 that resident in the term directory and term directory is under the div directory.
Sometimes user have to be away from his terminal, but don\'t want to logout because a job is running in the background.
This is done by lock command. It requires you to enter a password when you decide to lock it.
Syntax
<prompt> lock
Output
Password : ******
Re-enter password : ******
Terminal locked by Ram 0 minutes ago
There are two command in UNIX system to clear your screen clear and tput
Clear is used to clear the screen and cursor is positioned at the top left corner of the screen
tput is used with clear argument to clear the screen and with cup argument to position cursor at desired location.
Syntax:
<prompt>clear
<prompt>tput clear
<prompt>tput cup 10 10
cal command is used to see the calendar of specific month or a complete year.
To see the calendar of specific month of current year.
<prompt> cal mar
To see the calendar of specific year.
<prompt> cal 2006
bc command is used for calculator. When user invoke bc command without argument, the cursor keep on blinking
and nothing to seem to happen.
bc belongs to family of commands that accept input from keyboard.
Syntax <prompt> bc
bc command is used for calculator. When user invoke bc command without argument, the cursor keep on blinking
and nothing to seem to happen. bc belongs to family of commands that accept input from keyboard.
Syntax <prompt> bc
wc command is use to count lines, word and characters depending on theoption used. wc displays a four-columnar output.
Syntaxwc
cmp command is used to compare two file that they are identical or not. The two files are compared by byte and the location. If two files are identical, cmp display no message, but simply return the prompt.
Syntax:
<prompt> cmp file1 file2
The difference command is used to displaying file differences. It tell which linein one file have to be changed to make two files identical.
Syntaxcmp file1 file2
comm Command finds the text that is common to both the files and the text that is unique to both the files.
Syntax
<prompt> comm file1 file 2
The print commands allow us to print files to standard output (pr) or to a line printer (lp/lpr) while filtering the output.
Printing Commands
Command/Syntax What it will do
lpq (lpstat) [options] show the status of print jobs
lpr (lp) [options] file print to defined printer
lprm (cancel) [options] remove a print job from the print queue
lp and lpr command are used specified file or standard input to send to the printer to print. Each job is given a unique request-id that can be used to follow or cancel the job while it\'s in the queue.
Syntax:
lp [options] filename
lpr [options] filename
Common Options
lp lpr function
-n number -#number number of copies
-t title -Ttitle title for job
-d destination -Pprinter printer name
-c (default) copy file to queue before printing
(default) -s don�t copy file to queue before printing
-o option additional options
Examples
To print the file ssh.ps:
<prompt>lp ssh.ps
request id is lp-153 (1 file(s))
This submits the job to the queue for the default printer, lp, with the request-id lp-153.
User can check the status of your print job with lpstat or lpq.
Syntax:
lpstat [options]
lpq [options] [job#] [username]
Common Options
lpstat lpq function
-d (defaults to lp) list system default destination
-s summarize print status
-t print all status information
-u [login-ID-list] user list
-v list printers known to the system
-p -P list status of printer
Examples
<prompt> lpstat
lp-153 frank 208068 Apr 29 15:14 on lp
User can cancel only their own print jobs.
Syntax
cancel [request-ID] [printer]
lprm [options] [job#] [username]
Common Options
cancel lprm function
-Pprinter specify printer
all jobs for user
-u [login-ID-list] user list
User prepares files for printing in UNIX by using pr command. pr prints header and trailer information surrounding the formatted file. user can specify the number of pages, lines per page, columns, line spacing, page width, etc. to print, along with header and trailer information and how to treat <tab> characters.
Syntax
pr [options] file
Common Options
+page_number start printing with page page_number of the formatted input file
-column number of columns
-a modify -column option to fill columns in round-robin order
-d double spacing
-e[char][gap] tab spacing
-h header_string header for each page
-l lines lines per page
-t doesn\'t print the header and trailer on each page
-w width width of page
The shell sits between user and the operating system, acting as a command interpreter. The shell is same as command.com in DOS.
It reads user terminal input and translates the commands into actions taken by the system. When user log into the system user given a default shell.
When the shell starts up it reads its startup files and may set environment
variables, command search paths and executes any commands specified in these files.Shell is generally sleeping. It wakes up when input is typed at the prompt.
The following activities are typically performed by the shell.It issues the prompt and sleeps till user enter a command.
After a command has been entered, the shell scans the command line for special character that has special meaning for it.
It then creates a simplified command line and passes it on to the kernel for execution.The shell cannot do any work while the command is being executed and has to wait for its completion.After the job is complete, the prompt reappears and the shell return to sleeping.
There are following shell available in UNIX system
Shell Name Prompt
1) Bourne shell sh
2) C shell csh
3) Korn shell ksh
4) Bourne Again shell bash
5) T-C shell tcsh
6) Extended C-shell cshe
$ is the prompt for Bourne shell.
% is the prompt for c-shell.
The shells have a number of built-in, or native commands. These commands are executed directly in the shell and don\'t have to call another program to be run.
These built-in commands are different for the different shells.
For the Borne shell some of the more commonly used built-in commands are:
: null command
. source (read and execute) commands from a file
case case conditional loop
cd change the working directory (default is $HOME)
echo write a string to standard output
eval evaluate the given arguments and feed the result back to the shell
exec execute the given command, replacing the current shell
exit exit the current shell
export share the specified environment variable with subsequent shells
for for conditional loop
if if conditional loop
pwd print the current working directory
read read a line of input from stdin
set set variables for the shell
test evaluate an expression as true or false
trap trap for a typed signal and execute commands
umask set a default file permission mask for new files
unset unset shell variables
wait wait for a specified process to terminate
while while conditional loop
For the C shell the more commonly used built-in functions are:
alias assign a name to a function
bg put a job into the background
cd change the current working directory
echo write a string to stdout
eval evaluate the given arguments and feed the result back to the shell
exec execute the given command, replacing the current shell
exit exit the current shell
fg bring a job to the foreground
foreach for conditional loop
glob do filename expansion on the list, but no \"\" escapes are honored
history print the command history of the shell
if if conditional loop
jobs list or control active jobs
kill kill the specified process
limit set limits on system resources
logout terminate the login shell
nice command lower the scheduling priority of the process, command
nohup command do not terminate command when the shell exits
popd pop the directory stack and return to that directory
pushd change to the new directory specified and add the current one to the directory
rehash recreate the hash table of paths to executable files
repeat repeat a command the specified number of times
set set a shell variable
setenv set an environment variable for this and subsequent shells
source source (read and execute) commands from a file
stop stop the specified background job
switch switch conditional loop
umask set a default file permission mask for new files
unalias remove the specified alias name
unset unset shell variables
unsetenv unset shell environment variables
wait wait for all background processes to terminate
while while conditional loop
Environmental variables are used to provide information to the programs you use. User can have both global environment and local shell variables. Global environment variables are set by user login shell and new programs and shells inherit the environment of their parent shell.
Local shell variables are used only by that shell and are not passed on to other processes. A child process cannot pass a variable back to its parent process.
The current environment variables are displayed with the \"env\" or \"printenv\" commands.
Some common ones are:
DISPLAY The graphical display to use
EDITOR The path to your default editor
GROUP Your login group
HOME Path to your home directory
HOST The hostname of your system
IFS Internal field separators, usually any white space
LOGNAME The name you login with, e.g. frank
PATH Paths to be searched for commands
PS1 The primary prompt string, Bourne shell only
PS2 The secondary prompt string, Bourne shell only
SHELL The login shell you\'re using
TERM Your terminal type
USER Your username
\'Noclobber\' command indicates that output will not be redirected to existing files.
ignoreeof command specifies that EOF (^D) will not cause the login shell to exit and log you off the system.
With the history command user can recall previously executed commandsand re-execute them, with changes if desired.
An alias allows you to use the specified alias name instead of the full command.
In the \"ls\" example above, typing \"ls\" will result in \"/usr/bin/ls -sbF\" being executed.
User can put jobs into the background at anytime by appending \"&\" to the command.
After submitting a command you can also do this by typing ^Z (Control-Z) to suspend the job and then \"bg\" to put it into the background.
To bring background job to the foreground type \"fg\". Your keyboard is connected only to the current foreground job. With the %n notation you can reference the nth background job bring to fore ground. For Ex- To bring the third background job to the foreground with \"fg %3\".
User can use the history and savehist variables to set the number of previously executed commands to keep track of in this shell and how many to retain between logins, respectively. You could put a line such as the following in .cshrc to save the last 100 commands in this shell and the last 50 throughthe next login.
set history=100 savehist=50
Command Substitution Function
!! repeat last command
!n repeat command number n
!-n repeat command n from last
!str repeat command that started with string str
!?str? repeat command with str anywhere on the line
!?str?% select the first argument that had str in it
!: repeat the last command, generally used with a modifier
!:n select the nth argument from the last command (n=0 is the command name)
!:n-m select the nth through mth arguments from the last command
!^ select the first argument from the last command (same as !:1)
!$ select the last argument from the last command
!* select all arguments to the previous command
!:n* select the nth through last arguments from the previous command
!:n- select the nth through next to last arguments from the previous command
^str1^str2^ replace str1 with str2 in its first occurrence in the previous command
!n:s/str1/str2/ substitute str1 with str2 in its first occurrence in the nth command.
With output redirection, the output of a command is redirected to a file rather than to the terminal screen.
With input redirection, the input to a command is given via a file rather than the keyboard.
The standardized handling of data supports, there are two important features of UNIX utilities: I/O redirection and piping.
With output redirection, the output of a command is redirected to a file rather than to the terminal screen.
With input redirection, the input to a command is given via a file rather than the keyboard.
With piping, the output of a command can be used as input (piped) to a subsequent command.
There are 3 standard file descriptors:
stdin 0 Standard input to the program
stdout 1 Standard output from the program
stderr 2 Standard error output from the program
Output redirection takes the output of a command and places it into a named file. Input redirection reads the file as input to the command. The following table summarizes the redirection options.
File Redirection
Symbol Redirection
> output redirect
>! same as above, but overrides noclobber
>> append output
>>! same as above, but overrides
| pipe output to another command
< input redirection
<<String read from standard input until \"String\" is encountered as the only thing on the line.
<<String same as above, but don\'t allow shell substitutions
There are a number of other special symbols you can use on a command line.
These include:
; command separator
& run the command in the background
&& run the command following this only if the previous command completes successfully
|| run the command following only if the previous command did not complete successfully
( ) the commands within the parentheses are executed in a subshell.
. literal quotation marks. Don\'t allow any special meaning to any characters within these quotations.
escape the following character (take it literally)
\" \" regular quotation marks. Allow variable and command substitution with theses quotations
command take the output of this command and substitute it as an argument(s) on the command line
The shell and some text processing programs will allow meta-characters or wild cards and replace them with pattern matches.
For filenames these meta-characters and their uses are:
? match any single character at the indicated position
* match any string of zero or more characters
[abc...] match any of the enclosed characters
[a-e] match any characters in the range a,b,c,d,e
[!def] match any characters not one of the enclosed characters
{abc,bcd,cde} match any set of characters separated by comma (,) (no spaces)
~ home directory of the current user
Some text processing programs let you search on patterns instead of fixed strings. These text patterns are known as regular expressions. You form a regular expression by combining normal characters and special characters, also known as meta-characters, with the rules below. With these regular expressions you can do pattern matching on text data.Regular expressions come in three different forms:
- Anchors which tie the pattern to a location on the line
- Character sets which match a character at a single position
- Modifiers which specify how many times to repeat the previous expression
Some examples of the more commonly used regular expressions are:
Regular expression matches
cat the string cat
.at any occurrence of a letter, followed by at, such as cat, rat, mat, bat, fat, hat
xy*z any occurrence of an x, followed by zero or more y\'s, followed by a z.
^cat cat at the beginning of the line
cat$ cat at the end of the line
* any occurrence of an asterisk
[cC]at cat or Cat
[^a-zA-Z] any occurrence of a non-alphabetic character
[0-9]$ any line ending with a number
[A-Z][A-Z]* one or more upper case letters
[A-Z]* zero or more upper case letters (In other words, anything.)
Text Processing Commands
Command/Syntax What it will do
awk/nawk [options] file scan for patterns in a file and process the results
grep/egrep/fgrep [options] \' search string\' file search the argument for all occurrences of the search string, and list them.
sed [options] file stream editor for editing files from a script or from the command line.
The grep utility is used to search for generalized regular expressions occurring in Unix files. Regular expressions are best specified in apostrophes (or single quotes) when specified in the grep utility.
The egrep utility provides searching capability using an extended set of meta-characters.
Syntax
grep [options] regexp [file[s]]
Common Options
-i ignore case
-c report only a count of the number of lines containing matches, not the matches themselves
-v invert the search, displaying only lines that do not match
-n display the line number along with the line on which a match was found
-s work silently, reporting only the final status:
0, for match(es) found
1, for no matches
2, for errors
-l list filenames, but not lines, in which matches were found.
Command/Syntax What it will do
cmp [options] file1 file2 compare two files and list where differences occur (text or binary files)
cut [options] [file(s)] cut specified field(s)/character(s) from lines in file(s)
diff [options] file1 file2 compare the two files and display the differences (text files only)
file [options] file classify the file type
find directory [options] [actions] find files matching a type or pattern
ln [options] source_file target link the source_file to the target
paste [options] file paste field(s) onto the lines in file
sort [options] file sort the lines of the file according to the options chosen
strings [options] file report any sequence of 4 or more printable characters ending in <NL> / <NULL>.
tee [options] file copy stdout to one or more files
touch [options] [date] file create an empty file, or update the access time of an existing file
tr [options] string1 string2 translate the characters in string1 from stdin into those in string2 in stdout
uniq [options] file remove repeated lines in a file
wc [options] [file(s)] display word (or character or line) count for file(s)