Linux Shell Scripting Cookbook -- Table of Contents -- Linux Shell Scripting Cookbook -- Credits -- About the Authors -- About the Reviewers -- www.PacktPub.com -- Support files, eBooks, discount offers and more -- Why Subscribe? -- Free Access for Packt account holders -- Preface -- What this book covers -- What you need for this book -- Who this book is for -- Conventions -- Reader feedback -- Customer support -- Downloading the example code -- Errata -- Piracy -- Questions -- 1. Shell Something Out -- Introduction -- Printing in the terminal -- How to do it... -- How it works... -- There's more... -- Escaping newline in echo -- Printing a colored output -- Playing with variables and environment variables -- Getting ready -- How to do it... -- There's more... -- Finding the length of a string -- Identifying the current shell -- Checking for super user -- Modifying the Bash prompt string (username@hostname:~) -- Function to prepend to environment variables -- How to do it... -- How it works... -- Math with the shell -- Getting ready -- How to do it... -- Playing with file descriptors and redirection -- Getting ready -- How to do it... -- How it works... -- There's more... -- Redirection from a file to a command -- Redirecting from a text block enclosed within a script -- Custom file descriptors -- Arrays and associative arrays -- Getting ready -- How to do it... -- There's more... -- Defining associative arrays -- Listing of array indexes -- Visiting aliases -- How to do it... -- There's more... -- Escaping aliases -- Grabbing information about the terminal -- Getting ready -- How to do it... -- Getting and setting dates and delays -- Getting ready -- How to do it... -- How it works... -- There's more... -- Producing delays in a script -- Debugging the script -- How to do it... -- How it works... -- There's more... -- Shebang hack.

Functions and arguments -- How to do it... -- There's more... -- The recursive function -- Exporting functions -- Reading the return value (status) of a command -- Passing arguments to commands -- Reading the output of a sequence of commands in a variable -- Getting ready -- How to do it... -- There's more... -- Spawning a separate process with subshell -- Subshell quoting to preserve spacing and the newline character -- Reading n characters without pressing the return key -- How to do it... -- Running a command until it succeeds -- How to do it... -- How it works... -- There's more... -- A faster approach -- Adding a delay -- Field separators and iterators -- Getting ready -- How to do it... -- Comparisons and tests -- How to do it... -- 2. Have a Good Command -- Introduction -- Concatenating with cat -- How to do it... -- How it works… -- There's more... -- Getting rid of extra blank lines -- Displaying tabs as ^I -- Line numbers -- Recording and playing back of terminal sessions -- Getting ready -- How to do it... -- How it works... -- Finding files and file listing -- Getting ready -- How to do it... -- There's more... -- Search based on filename or regular expression match -- Negating arguments -- Search based on the directory depth -- Search based on file type -- Search on file times -- Search based on file size -- Deleting based on the file matches -- Match based on the file permissions and ownership -- Executing commands or actions with find -- Skipping specified directories when using the find command -- Playing with xargs -- Getting ready -- How to do it... -- How it works… -- There's more... -- Passing formatted arguments to a command by reading stdin -- Using xargs with find -- Counting the number of lines of C code in a source code directory -- While and subshell trick with stdin -- Translating with tr -- Getting ready -- How to do it...

How it works… -- There's more... -- Deleting characters using tr -- Complementing character set -- Squeezing characters with tr -- Character classes -- Checksum and verification -- Getting ready -- How to do it... -- How it works... -- There's more... -- Checksum for directories -- Cryptographic tools and hashes -- How to do it... -- Sorting unique and duplicates -- Getting ready -- How to do it... -- How it works… -- There's more... -- Sorting according to the keys or columns -- uniq -- Temporary file naming and random numbers -- How to do it... -- How it works… -- Splitting files and data -- How to do it... -- There's more… -- Specifying a filename prefix for the split files -- Slicing filenames based on extension -- How to do it… -- How it works… -- Renaming and moving files in bulk -- Getting ready -- How to do it... -- How it works… -- Spell checking and dictionary manipulation -- How to do it... -- How it works... -- Automating interactive input -- Getting ready -- How to do it... -- How it works… -- There's more... -- Automating with expect -- Making commands quicker by running parallel processes -- How to do it... -- How it works... -- 3. File In, File Out -- Introduction -- Generating files of any size -- How to do it... -- The intersection and set difference (A-B) on text files -- Getting ready -- How to do it... -- How it works... -- Finding and deleting duplicate files -- Getting ready -- How to do it... -- How it works... -- Working with file permissions, ownership, and the sticky bit -- How to do it... -- There's more... -- Changing ownership -- Setting sticky bit -- Applying permissions recursively to files -- Applying ownership recursively -- Running an executable as a different user (setuid) -- Making files immutable -- Getting ready -- How to do it... -- Generating blank files in bulk -- Getting ready -- How to do it...

Finding symbolic links and their targets -- How to do it... -- How it works... -- Enumerating file type statistics -- Getting ready -- How to do it... -- How it works... -- Using loopback files -- How to do it... -- How it works... -- There's more... -- Creating partitions inside loopback images -- Quicker way to mount loopback disk images with partitions -- Mounting ISO files as loopback -- Flush changing immediately with sync -- Creating ISO files and hybrid ISO -- Getting ready -- How to do it... -- There's more... -- Hybrid ISO that boots off a flash drive or hard disk -- Burning an ISO from the command line -- Playing with the CD-ROM tray -- Finding the difference between files, patching -- How to do it... -- There's more... -- Generating difference against directories -- Using head and tail for printing the last or first 10 lines -- How to do it... -- Listing only directories - alternative methods -- Getting ready -- How to do it... -- How it works... -- Fast command-line navigation using pushd and popd -- Getting ready -- How to do it... -- There's more... -- Most frequently used directory switching -- Counting the number of lines, words, and characters in a file -- How to do it... -- Printing the directory tree -- Getting ready -- How to do it... -- There's more... -- HTML output for tree -- 4. Texting and Driving -- Introduction -- Using regular expressions -- How to do it... -- How it works... -- There's more... -- Treatment of special characters -- Visualizing regular expressions -- Searching and mining a text inside a file with grep -- How to do it... -- There's more... -- Recursively search many files -- Ignoring case of pattern -- grep by matching multiple patterns -- Including and excluding files in a grep search -- Using grep with xargs with zero-byte suffix -- Silent output for grep -- Printing lines before and after text matches.

Cutting a file column-wise with cut -- How to do it... -- There's more -- Specifying the range of characters or bytes as fields -- Using sed to perform text replacement -- How to do it… -- There's more... -- Removing blank lines -- Performing replacement directly in the file -- Matched string notation (&) -- Substring match notation (\1) -- Combination of multiple expressions -- Quoting -- Using awk for advanced text processing -- Getting ready... -- How to do it… -- How it works… -- There's more… -- Special variables -- Passing an external variable to awk -- Reading a line explicitly using getline -- Filtering lines processed by awk with filter patterns -- Setting delimiter for fields -- Reading the command output from awk -- Using loop inside awk -- String manipulation functions in awk -- Finding the frequency of words used in a given file -- Getting ready -- How to do it... -- How it works... -- See also -- Compressing or decompressing JavaScript -- Getting ready -- How to do it... -- How it works... -- See also -- Merging multiple files as columns -- How to do it... -- See also -- Printing the nth word or column in a file or line -- How to do it... -- See also -- Printing text between line numbers or patterns -- Getting ready -- How to do it... -- See also -- Printing lines in the reverse order -- Getting ready -- How to do it... -- How it works... -- Parsing e-mail addresses and URLs from text -- How to do it... -- How it works... -- See also -- Removing a sentence in a file containing a word -- Getting ready -- How to do it... -- How it works... -- See also -- Replacing a pattern with text in all the files in a directory -- How to do it... -- How it works... -- There's more... -- Text slicing and parameter operations -- How to do it... -- See also -- 5. Tangled Web? Not At All! -- Introduction -- Downloading from a web page -- Getting ready.

How to do it...