linux unix commands with examples

Unix/Linux Commands

Ls: List of all files

Syntax	Function
Ls-l	Complete properties of files or folders
Ls-lt	List of files or folders order by time
Ls-ltr	List of files or folders reverse order by time
Ls-d	Displays only directories

Cd: Change directory

Syntax	Function
cd-	Change directory to previous working directory
cd..	Change working directory to parent directory
Cd~	Same as above
cd../..	Change two levels up in the directory structure

Command	Syntax	Function
Cp(copy)	Cp source..destination	Copy the files and directories
sort	Sort[option][filename]	Sort the contents of text line by line
uniq	Uniq[option] filename	Eliminates duplicate lines from file
cat	Cat[options][files]	Display the contents of the file
join	Join[option]file1 file2	Join he two files based on key field present
sed	Sed..[script][input file]	Basic text transformations on input
head	head[option][files]	Prints first N lines from file
tail	Tail[option][file]	Print last N lines from file
alias	Alias[name=[’command]’]	Alternative name used for long strings
date	Date[option]…[format]	Print the date or change the system date and time
zip	Zip[option]zipfile file_list	Compress the file and reduce file size
grep	Grep[option]pattern[list of files]	Search the words in a file
find	Find[pathnames][condition]	Search for directories, files and links
cut	Cut[option]…[file]	Select sections of text from each line in a file
chmod	Chmod[option]mode… filename	Change or assign the permissions of files or directories
rmdir	Rmdir[options]directories	Remove directories
rm	Rm[options]directories/files	Remove both files and directories
mkdir	Mkdir[option]directories	Creates single or multiple directories
mv(move)	Mv[option]source.. destin	Move or rename the files and directories
hostname	Hostname[option][file]	Name of the system or server you are logged into.
paste	Paste[options]file-list	Merges the lines from multiple files
split	Split..filename	Split the one file in to many pieces
mail	Mail[options]to address [sending mail options]	Send email to users, also read delete mails
kill	Kill[-s signal] pid	Terminate or kill the process, also running the process
top	Top[options]	Provides system information
expr	Expr[expression]	For doing arithmetic operations
WC	Wc[options]filename	Finding number of lines, characters, words in a file
tr (Translate)	Tr[options]set1 [set2]	Translate, delete, squeezed characters