Index

A

• absolute paths
  • about / How it works...
• active user hours, system
  • monitoring / Finding out active user hours on a system, Getting ready, How to do it…
• active_users.sh script / How it works…
• addgroup command
  • about / How it works…
• administrative user root
  • about / Introduction
• advanced text processing
  • awk command, used / Using awk for advanced text processing
• alias
  • about / Visiting aliases
  • visiting / Visiting aliases, How to do it...
  • escaping / Escaping aliases
• arbitrary sockets
  • creating / Creating arbitrary sockets, How to do it...
• archives
  • creating, tar command used / Archiving with tar
  • creating, cpio used / Archiving with cpio, How to do it...
  • creating, zip command used / Archiving and compressing with zip
  • creating, pbzip2 command used / Faster archiving with pbzip2
• archives, tar command used
  • files, appending to / Appending files to an archive
  • files, extracting / Extracting files and folders from an archive
  • folders, extracting / Extracting files and folders from an archive
  • concatenating / Concatenating two archives
  • files, updating with timestamp check / Updating files in an archive with a timestamp check
  • files, comparing / Comparing files in the archive and file system
  • files, deleting / Deleting files from the archive
  • tar archive, compressing / Compression with the tar archive
  • file set, excluding / Excluding a set of files from archiving
  • version control directories, excluding / Excluding version control directories
  • total bytes, printing / Printing total bytes
• arguments
  • passing, to commands / Passing arguments to commands
• arithmetic operations
  • about / Math with the shell
  • performing / Math with the shell, How to do it...
• array indexes
  • listing / Listing of array indexes
• arrays
  • about / Arrays and associative arrays
  • associative arrays / Arrays and associative arrays
• aspell command
  • about / Spell checking and dictionary manipulation
  • working / How it works...
• aspell list command
  • about / How it works...
• associative arrays
  • using / Getting ready, How to do it...
  • about / There's more...
  • defining / Defining associative arrays
• asymmetric keys / Getting ready
• auto-login
  • SSH keys used / Password-less auto-login with SSH
• automatic authentication
  • setting up, SSH keys used / How to do it...
• awk command
  • used, for advanced text processing / Using awk for advanced text processing, How it works…
  • working / How it works…
  • special variables / Special variables
  • external variable. passing to / Passing an external variable to awk
  • line, reading explicitly / Reading a line explicitly using getline
  • lines, filtering / Filtering lines processed by awk with filter patterns
  • delimiter, setting for fields / Setting delimiter for fields
  • command output, reading / Reading the command output from awk
  • for loop, using / Using loop inside awk
  • string manipulation functions / String manipulation functions in awk
• awk utility / How to do it…

B

• back quotes / How to do it...
• back tick / How to do it...
• bandwidth limit
  • specifying, on cURL / Specifying a bandwidth limit on cURL
• base64 command
  • about / How to do it...
• Bash
  • MySQL database, reading from / Writing and reading the MySQL database from Bash, How to do it…, How it works…
  • MySQL database, writing to / Writing and reading the MySQL database from Bash, How to do it…, How it works…
• Bash (Bourne Again Shell)
  • about / Introduction
• bash-oauth library
  • downloading / Getting ready
• bash prompt string
  • modifying / Modifying the Bash prompt string (username@hostname:~$)
• bc
  • about / How to do it...
• BEGIN block / How it works…
• blank files
  • generating, in bulk / Generating blank files in bulk
• boot failures, machine
  • obtaining / How to do it...
• boot logs, machine
  • obtaining / How to do it...
• broken links, website
  • identifying / Finding broken links in a website, How to do it..., How it works...
• bzip2 command
  • about / Using bzip2

C

• --convert-links option / Copying a complete website (mirroring)
• cat command
  • about / Concatenating with cat
  • general syntax / How to do it...
  • data, concatenating with / How to do it...
  • working / How it works…
  • extra blank lines, removing / Getting rid of extra blank lines
  • tabs, displaying as ^I / Displaying tabs as ^I
  • line numbers / Line numbers
• CD-ROM tray / Playing with the CD-ROM tray
• cd command
  • about / Spawning a separate process with subshell
• cdrecord command
  • used, for burning ISO / Burning an ISO from the command line
• chage command
  • about / How it works…
• chain / How it works...
• changes, website
  • tracking / Tracking changes to a website, How to do it..., How it works...
• character classes, tr command
  • alnum / Character classes
  • alpha / Character classes
  • cntrl / Character classes
  • digit / Character classes
  • graph / Character classes
  • lower / Character classes
  • print / Character classes
  • punct / Character classes
  • space / Character classes
  • upper / Character classes
  • xdigit / Character classes
• characters, files
  • counting, wc command used / How to do it...
• chattr command
  • used, for making file immutable / Getting ready
• checksums
  • about / Checksum and verification, There's more...
  • calculating / Checksum and verification
  • computing / Checksum and verification
  • for directories / Checksum for directories
• checksum verification
  • about / How it works...
• chmod command
  • about / How to do it...
  • using, for setting file permissions / How to do it...
• chsh command
  • about / How it works…
• colored output
  • printing / Printing a colored output
• command-line navigation
  • pushd and popd command used / Fast command-line navigation using pushd and popd, How to do it...
• command-line options, comm command
  • about / How it works...
• command execution time
  • calculating, time command used / Calculating the execution time for a command, How to do it...
  • real time / How it works...
  • user time / How it works...
  • sys time / How it works...
• command line
  • Gmail e-mails, accessing from / Accessing Gmail e-mails from the command line
• command outputs
  • monitoring, watch command used / Monitoring command outputs with watch
• commands
  • running / Running a command until it succeeds
  • faster approach / A faster approach
  • delay, adding / Adding a delay
  • executing rapidly / Making commands quicker by running parallel processes, How it works...
  • executing on remote host, with SSH / Running commands on a remote host with SSH, How to do it...
  • running, at system boot / Running commands at system start up/boot
• Comma Separated Values (CSV) / Writing and reading the MySQL database from Bash
• comma separated values (CSV)
  • about / Field separators and iterators
• comm command
  • about / Getting ready, How to do it...
• comparisons
  • about / Comparisons and tests
  • mathematical comparisons, performing / How to do it...
  • string comparisons, performing / How to do it...
• compression command
  • about / How it works...
• Content-length parameter / Printing response headers excluding the data
• convert command
  • about / Getting ready
• Coordinated Universal Time (UTC) / How it works...
• cpio command
  • about / Archiving with cpio
  • used, for archiving / Archiving with cpio, How to do it...
  • working / How it works...
• CPU
  • about / Listing the top 10 CPU consuming processes in an hour
• CPU usage
  • monitoring, ps command used / Getting ready, How to do it..., How it works...
• cron
  • scheduling with / Scheduling with cron, Getting ready, How it works...
• cron scheduling utility
  • about / Getting ready
• crontab command
  • about / Getting ready
  • environment variables, specifying / Specifying environment variables
  • specific commands, running at system boot / Running commands at system start up/boot
• cron table / Scheduling with cron
  • viewing / Viewing the cron table
  • removing / Removing the cron table
• crypt command
  • about / How to do it...
• cryptographic tools
  • crypt command / How to do it...
  • gpg / How to do it...
  • base64 / How to do it...
  • SHA-1 / How to do it...
  • md5sum / How to do it...
  • shadow-like salted hash / How to do it...
• csplit
  • about / Specifying a filename prefix for the split files
• cURL
  • about / A primer on cURL
  • features / A primer on cURL
  • tasks / How to do it…
  • working / How it works...
  • downloads, resuming / Continuing and resuming downloads
  • referer string, setting / Setting the referer string with cURL
  • cookies, storing / Cookies with cURL
  • user agent string, setting / Setting a user agent string with cURL
  • bandwidth limit, specifying / Specifying a bandwidth limit on cURL
  • maximum download size, specifying / Specifying the maximum download size
  • authentication / Authenticating with cURL
  • response headers, printing / Printing response headers excluding the data
• curl command
  • about / How to do it…
• custom echo script
  • writing / Passing formatted arguments to a command by reading stdin
• custom file descriptors
  • about / Custom file descriptors
• cut command
  • used, for cutting file column-wise / How to do it...
  • range of characters, specifying as fields / Specifying the range of characters or bytes as fields

D

• data
  • concatenating, with cat command / Concatenating with cat
  • parsing, from website / Parsing data from a website
  • compressing, gzip used / Compressing data with gzip, How to do it...
  • backing up, rsync command used / Backup snapshots with rsync, How to do it...
• date format / How it works...
• dates and time delays
  • working with / Getting and setting dates and delays, How to do it..., How it works...
• dd command
  • about / How to do it...
• decompression command
  • about / How it works...
• define utility
  • creating, Web backend used / Creating a "define" utility by using the Web backend, Getting ready, How to do it...
  • code / How to do it...
  • working / How it works...
• delays
  • executing, in script / Producing delays in a script
• delgroup command
  • about / How it works…
• deluser command
  • about / How it works…
• df command
  • used, for calculating disk usage / Getting ready
  • about / Getting ready
• dictionary file
  • using / Spell checking and dictionary manipulation
• diff command
  • used, for generating difference files / How to do it...
• difference file
  • about / Finding the difference between files, patching
  • generating, diff command used / How to do it...
  • generating, against directories / Generating difference against directories
• difference operation, text files
  • about / Getting ready
• directories
  • listing, dir command used / Getting ready, How it works...
• directory access
  • monitoring, inotifywait command used / How to do it...
• directory tree, files
  • printing / Printing the directory tree, How to do it...
  • HTML output / HTML output for tree
• disk activity
  • monitoring, iotop command used / Monitoring disk activity, How to do it...
• disk images
  • creating, fsarchiver used / Creating entire disk images using fsarchiver, How it works...
• disks
  • checking for errors, fsck used / Getting ready, How to do it..., How it works...
• disk space
  • about / Monitoring disk usage
• disk usage
  • monitoring / Monitoring disk usage, There's more...
  • displaying in units, with du command / Displaying disk usage in KB, MB, or Blocks
• disk usage statistics, remote machine
  • monitoring / Remote disk usage health monitor, How to do it…, How it works…
• DNS servers
  • about / Name server and DNS (Domain Name Service)
  • DNS lookup utilities / DNS lookup
• domain names
  • about / Name server and DNS (Domain Name Service)
• du command
  • about / Getting ready
  • used, for calculating disk usage / Getting ready
• du command, functionalities
  • disk usage, displaying in units / Displaying disk usage in KB, MB, or Blocks
  • total disk size, displaying / Displaying the grand total sum of disk usage
  • files, printing in specified units / Printing files in specified units
  • files, excluding from disk usage calculation / Excluding files from the disk usage calculation
  • largest size files, searching from directory / Finding the 10 largest size files from a given directory
  • disk free information, providing / Disk free information
• duplicate files
  • about / Finding and deleting duplicate files
  • searching / Finding and deleting duplicate files, How it works...
  • deleting / Getting ready, How it works...

E

• #expect parameter
  • about / Automating with expect
• </entry> element / How it works...
• e-mail addresses
  • parsing, from text / Parsing e-mail addresses and URLs from text, How it works...
• echo command
  • about / How to do it...
  • newline, escaping / Escaping newline in echo
• egrep regex pattern / How to do it...
• encryption techniques
  • about / Cryptographic tools and hashes
• END block / How it works…
• environment variables
  • about / Playing with variables and environment variables
  • displaying, for processes / Showing environment variables for a process
  • specifying / Specifying environment variables
• epoch / Getting ready
• ESSID
  • about / Connecting to a wireless network
• Ethernet connection
  • about / Connecting to a wireless network
• event loop
  • about / Capturing and responding to signals
• exit status / Reading the return value (status) of a command
• expect command
  • automating / Automating with expect
• expect command
  • interactive input, automating / Automating with expect
• export command
  • about / How to do it...
• expr
  • about / How to do it...
• ext4 filesystem
  • creating / How to do it...
  / Creating entire disk images using fsarchiver
• extfs (extended FS)
  • file permissions / Working with file permissions, ownership, and the sticky bit

F

• file access
  • monitoring, inotifywait command used / Getting ready
• file command
  • about / Getting ready, About which, whereis, file, whatis, and load average
  • using / Getting ready
• file descriptors
  • about / Playing with file descriptors and redirection
  • working with / How to do it...
• filenames
  • slicing, based on extension / Slicing filenames based on extension, How it works…
• file permissions
  • about / Working with file permissions, ownership, and the sticky bit
  • ownership / Working with file permissions, ownership, and the sticky bit
  • user / Working with file permissions, ownership, and the sticky bit
  • group / Working with file permissions, ownership, and the sticky bit
  • others / Working with file permissions, ownership, and the sticky bit
  • listing, ls -l command used / Working with file permissions, ownership, and the sticky bit
  • setting, chmod command used / How to do it...
  • removing / How to do it...
  • ownership, changing / Changing ownership
  • sticky bit, setting / Setting sticky bit
  • applying recursively / Applying permissions recursively to files
  • ownership, applying recursively / Applying ownership recursively
  • executable, running as setuid / Running an executable as a different user (setuid)
• files
  • locating, with find command / Getting ready, How to do it...
  • renaming, rename command used / Renaming and moving files in bulk
  • generating / Generating files of any size, How to do it...
  • intersection operation / Getting ready
  • difference operation / Getting ready
  • set difference operation / Getting ready
  • duplicate files, finding / Finding and deleting duplicate files
  • duplicate files, deleting / Finding and deleting duplicate files
  • file permissions, working with / Working with file permissions, ownership, and the sticky bit
  • making immutable / Making files immutable
  • blank files, generating in bulk / Generating blank files in bulk, How to do it...
  • symbolic links, searching / Finding symbolic links and their targets
  • file type statistics, enumerating / Enumerating file type statistics
  • loopback files, using / Using loopback files
  • ISO files, creating / Creating ISO files and hybrid ISO
  • hybrid ISO, creating / Creating ISO files and hybrid ISO
  • difference file, searching / Finding the difference between files, patching
  • difference file, patching / Finding the difference between files, patching
  • last or first 10 lines, printing / Using head and tail for printing the last or first 10 lines, How to do it...
  • directories, listing / Listing only directories – alternative methods
  • counting / Counting the number of lines, words, and characters in a file
  • directory tree, printing / Printing the directory tree
  • text, searching with grep command / Searching and mining a text inside a file with grep
  • column-wise cutting, with cut command / Cutting a file column-wise with cut, How to do it..., There's more
  • transfering, through network / Transferring files through the network, How to do it...
  • copying, over network / Quickly copying files over the network
• files and data
  • spiltting, spilt command used / Splitting files and data
• filesystem backup solution / Creating entire disk images using fsarchiver
• filesystems
  • checking for errors, fsck used / Getting ready, How to do it..., How it works...
• file type statistics
  • enumerating / Enumerating file type statistics, How to do it..., How it works...
• filters / Getting ready
• find command
  • about / Finding files and file listing
  • used, for searching files / Getting ready, How to do it...
  • used, for listing files / Getting ready, How to do it...
  • searching, based on filename / Search based on filename or regular expression match
  • searching, based on regular expression match / Search based on filename or regular expression match
  • arguments, negating / Negating arguments
  • searching, based on directory depth / Search based on the directory depth
  • searching, based on file type / Search based on file type
  • searching, based on file times / Search on file times
  • searching, based on file size / Search based on file size
  • deleting, based on file matches / Deleting based on the file matches
  • match, based on file permissions and ownership / Match based on the file permissions and ownership
  • executing / Executing commands or actions with find
  • specified directories, skipping / Skipping specified directories when using the find command
• finger USER command
  • about / How it works…
• firewall
  • about / Basic firewall using iptables
• formatted arguments
  • passing to xargs command / Passing formatted arguments to a command by reading stdin
• fping command
  • used, for listing live machines on network / Getting ready, Using fping
• frequency of words
  • finding, in file / Finding the frequency of words used in a given file, How to do it...
• Frequency parameter / How it works...
• fsarchiver
  • about / Creating entire disk images using fsarchiver
  • used, for creating disk images / Creating entire disk images using fsarchiver, How it works...
  • URL / Getting ready
  • working / How it works...
• fsck command
  • used, for checking disks and filesystem / Getting ready, How to do it..., How it works...
• FTP
  • about / How to do it...
  • using / How to do it...
  • connecting to / How to do it...
  • automated FTP transfer / Automated FTP transfer
  • SFTP / SFTP (Secure FTP)
  • rsync command / The rsync command
  • SCP / SCP (secure copy program)
  • recursive copying, with SCP / Recursive copying with SCP
• FTP authentication, cURL
  • about / Authenticating with cURL
• functions
  • defining / Functions and arguments, How to do it...
  • exporting / Exporting functions

G

• gateway / Showing routing table information
• gedit / Getting ready
• GET request / Posting to a web page and reading the response
• Git
  • about / Version control-based backup with Git
  • used, for version control based backup / Version control-based backup with Git, How to do it...
• Gmail
  • about / Accessing Gmail e-mails from the command line
• Gmail e-mails
  • accessing, from command line / Accessing Gmail e-mails from the command line, How it works...
• GNU/Linux ecosystem
  • about / Introduction
• GNU screen / Getting ready
• gpg command / How to do it...
• grep command
  • about / How to do it...
  • using / How to do it...
  • files, searching recursively / Recursively search many files
  • multiple patterns, matching / grep by matching multiple patterns
  • files, including in search / Including and excluding files in a grep search
  • files, excluding in search / Including and excluding files in a grep search
  • using with xargs with zero-byte suffix / Using grep with xargs with zero-byte suffix
  • silent output / Silent output for grep
  • lines, printing / Printing lines before and after text matches
• group, file permissions
  • about / Working with file permissions, ownership, and the sticky bit
• gzip command
  • about / Compressing data with gzip
  • used, for compressing data / Compressing data with gzip, How to do it...
• gzip command, features
  • gzipped tarball, creating / Gzip with tarball
  • compression ratio, specifying / Compression ratio
  • bzip2, using / Using bzip2
  • lzma using / Using lzma
• gzipped tarball
  • creating / Gzip with tarball

H

• hardware address
  • spoofing / Spoofing the hardware address (MAC address)
• head and tail commands
  • used, for printing last or first 10 lines / Using head and tail for printing the last or first 10 lines, How to do it...
• head command
  • about / How to do it...
• HTML output, directory tree
  • about / HTML output for tree
• HTTP authentication, cURL
  • about / Authenticating with cURL
• HTTP or FTP authentication
  • used, for accessing web pages / Accessing pages with HTTP or FTP authentication
• HTTP protocol / Introduction
• HTTP_PROXY
  • about / How to do it...
• hybrid ISO
  • creating / Creating ISO files and hybrid ISO, Hybrid ISO that boots off a flash drive or hard disk

I

• <img> tags
  • about / Web photo album generator
• ifconfig command
  • about / Getting ready
  • used, for displaying network interfaces / Getting ready
• IFS
  • about / Field separators and iterators
  • using / How to do it...
  • example / How to do it...
• image
  • format, converting / Bulk image resizing and format conversion, How to do it.., How it works…
  • resizing / Bulk image resizing and format conversion, How to do it.., How it works…
• image crawlers
  • about / Image crawler and downloader
  • working / How it works...
• Image crawlers
  • working / How it works...
• image downloader
  • about / How it works...
• Imagemagick
  • about / Getting ready
  • URL / Getting ready
• import command / How to do it...
• information, about processes
  • gathering, ps command used / How to do it...
• inotifywait command
  • used, for monitoring file and directory access / Getting ready
  • working / How it works...
• interactive input
  • automating / Automating interactive input, How to do it...
• internal field separator / How it works…
• Internal Field Separator (IFS) / How it works…
• Internet connection
  • sharing / Sharing an Internet connection, How to do it...
• Internet Control Message Protocol (ICMP) echo packets / How to do it...
• Internet Explorer (IE) / Setting a user agent string with cURL
• intersection operation, text files
  • about / Getting ready
  • performing / How to do it...
• intruder_detect.sh script
  • writing / Getting ready, How it works…
• iotop command
  • used, for monitoring disk activity / Monitoring disk activity, How to do it...
• IP addresses
  • displaying / Displaying IP addresses
• iptables
  • using / Basic firewall using iptables, How to do it...
  • working / How it works...
• ISO files
  • about / Creating ISO files and hybrid ISO
  • creating / Creating ISO files and hybrid ISO
  • burning, from command line / Burning an ISO from the command line
• isohybrid command
  • used, for converting ISO files to hybrid ISOs / Hybrid ISO that boots off a flash drive or hard disk
• ISO image
  • creating / Creating ISO files and hybrid ISO
• iwconfig command / How it works...
  • using / Getting ready, How to do it...

J

• JavaScript
  • compressing / Compressing or decompressing JavaScript, How to do it...
  • decompressing / Getting ready, How to do it...

K

• killall command
  • about / The kill family of commands
• kill command
  • about / Getting ready, The kill family of commands
• Konsole / Managing multiple terminals from one
• kpartx
  • about / Quicker way to mount loopback disk images with partitions

L

• --limit-rate argument / Restricting the download speed
• --limit-rate option / Specifying a bandwidth limit on cURL
• Last-Modified parameter / Printing response headers excluding the data
• last command
  • obtaining / How to do it...
• last in first out (LIFO)
  • about / Getting ready
• last or first 10 lines
  • about / Getting ready
  • working / How it works...
• let command
  • about / How to do it...
• lines, files
  • counting, wc command used / How to do it...
  • printing, in reverse order / Printing lines in the reverse order, How it works...
• Lines of Code (LOC) / Counting the number of lines of C code in a source code directory
• Linux
  • disk usage, calculating with df and du / Getting ready
• live machines
  • listing, on network / Listing all the machines alive on a network, Getting ready, How it works...
  • listing, on network with ping command / How to do it...
  • listing, on network with fping command / How to do it...
• load average command
  • about / About which, whereis, file, whatis, and load average
• LOC (Lines of Code)
  • about / Counting the number of lines, words, and characters in a file
• local mount point
  • remote drive, mounting / Mounting a remote drive at a local mount point
• log events
  • access / How it works...
  • modify / How it works...
  • attrib / How it works...
  • move / How it works...
  • create / How it works...
  • open / How it works...
  • close / How it works...
  • delete / How it works...
• logfile management
  • performing, logrotate command used / Logfile management with logrotate, Getting ready, How it works...
• logfiles
  • writing into / Getting ready
• logged in users information
  • obtaining / How to do it...
• logrotate command
  • used, for logfile management / Logfile management with logrotate, Getting ready, How it works...
  • missingok parameter / How it works...
  • notifempty parameter / How it works...
  • size 30k parameter / How it works...
  • compress parameter / How it works...
  • weekly parameter / How it works...
  • rotate 5 parameter / How it works...
  • create 0600 root root parameter / How it works...
• look command
  • about / How it works...
• loopback disk images
  • mounting, with partitions / Quicker way to mount loopback disk images with partitions
• loopback files
  • about / Generating files of any size
  • using / Using loopback files, How to do it...
  • partitions, creating inside images / Creating partitions inside loopback images
  • ISO files, mounting / Mounting ISO files as loopback
  • changes, flushing with sync command / Flush changing immediately with sync
• losetup command / How it works...
• ls -lS command
  • about / How it works...
• Lynx
  • about / Downloading a web page as plain text
  • working / How it works...
• lynx command / How to do it...
• lzma command
  • about / Using lzma

M

• --max-depth parameter / Excluding files from the disk usage calculation
• --mirror option / Copying a complete website (mirroring)
• -max-filesize option / Specifying the maximum download size
• man-in-the-middle attack / How to do it...
• mathematical comparisons
  • performing / How to do it...
• maximum download size, for cURL
  • specifying / Specifying the maximum download size
• md5sum
  • about / How to do it...
• md5sum checksum
  • about / Getting ready, How it works...
  • computing / How to do it...
  • syntax / How it works...
• md5sum command
  • about / How to do it...
• messages
  • sending, to user terminals / Sending messages to user terminals, How it works...
• minified JS / Compressing or decompressing JavaScript
• mkdir command / How it works...
• mkfs command / How to do it...
• mkfts.ext4 command / How it works...
• mkisofs command
  • about / How to do it...
• mktemp command
  • about / Temporary file naming and random numbers
  • temporary file, creating / How to do it...
  • working / How it works…
• mount command
  • about / Generating files of any size, How it works...
• mountpoint
  • about / Using loopback files, How it works...
• multiple commands
  • combining / Reading the output of a sequence of commands in a variable
• multiple files
  • merging, as columns / Merging multiple files as columns
• multiple tar files
  • concatenating / Concatenating two archives
• multiple terminals
  • manging, from one / Managing multiple terminals from one, How to do it...
• MySQL database
  • about / Writing and reading the MySQL database from Bash
  • reading, from Bash / Writing and reading the MySQL database from Bash, How to do it…, How it works…
  • writing, to Bash / Writing and reading the MySQL database from Bash, How to do it…, How it works…

N

• -nolist option / How it works...
• n characters
  • reading, without return key / Reading n characters without pressing the return key
• netcat command
  • used, for creating arbitrary sockets / Creating arbitrary sockets, How to do it...
• netstat command
  • about / Opened port and services using netstat
• network
  • setting up / Setting up the network
• Network Address Translation (NAT)
  • setting up / Getting ready
• networking
  • about / Introduction
• networking parameters
  • subnet mask / Introduction
  • route / Introduction
  • ports / Introduction
  • host names / Introduction
• network interface
  • about / Getting ready
• network ports
  • about / Network traffic and port analysis, How to do it...
• network setup
  • performing / Setting up the network, How to do it...
  • network interfaces list, printing / Printing the list of network interfaces
  • IP addresses, displaying with ifconfig command / Displaying IP addresses
  • hardware address, spoofing / Spoofing the hardware address (MAC address)
  • domain names / Name server and DNS (Domain Name Service)
  • DNS / Name server and DNS (Domain Name Service)
  • routing table information, displaying / Showing routing table information
  • ping command / Let us ping!
  • live machines, listing on network / Listing all the machines alive on a network
  • commands, running on remote host with SSH / Running commands on a remote host with SSH
  • files, transfering through network / Transferring files through the network
  • wireless network, connecting to / Connecting to a wireless network
  • password-less auto-login, with SSH / Password-less auto-login with SSH
  • port forwarding, with SSH / Port forwarding using SSH
  • remote drive, mounting at local mount point / Mounting a remote drive at a local mount point
  • network traffic / Network traffic and port analysis
  • port analysis / Network traffic and port analysis
  • arbitrary sockets, creating / Creating arbitrary sockets
  • Internet connection, sharing / Sharing an Internet connection
  • firewall, iptables used / Basic firewall using iptables
• non-interactive port forward
  • about / Non-interactive port forward
• nth word or column, in file
  • printing / Printing the nth word or column in a file or line

O

• %% operator
  • about / How it works…
• % operator / How it works…
• (( )) operator
  • about / How to do it...
• OAuth
  • about / Getting ready
• opened port
  • listing / Opened port and services using netstat
• others, file permissions
  • about / Working with file permissions, ownership, and the sticky bit
• output, multiple commands
  • reading / Reading the output of a sequence of commands in a variable, Getting ready

P

• --password argument / Accessing pages with HTTP or FTP authentication
• /proc
  • used, for obtaining information / Using /proc for gathering information
• parameter operations
  • about / Text slicing and parameter operations, How to do it...
• partimage
  • about / Creating entire disk images using fsarchiver
• passwd command
  • about / How it works…
• paste command
  • about / How to do it...
• patch command
  • used, for patching difference file / Finding the difference between files, patching
• patch file
  • about / Finding the difference between files, patching
  • generating / How to do it...
  • changes, reverting / How to do it...
• PATH environment variable
  • about / How to do it...
• pattern
  • replacing, with text in all files in directory / Replacing a pattern with text in all the files in a directory, How to do it...
• pbzip2 command
  • used, for archiving / Faster archiving with pbzip2, How to do it...
  • working / How it works...
• pbzip2 command, features
  • number of CPUs, specifying / Manually specifying the number of CPUs
  • compression ratio, specifying / Specifying the compression ratio
• pcpu command
  • about / How to do it...
• pgrep command / Getting ready, Finding the process ID when given command names
• PHP / Introduction
• PID
  • about / Gathering information about processes
• ping command
  • about / Let us ping!
  • using / How to do it...
  • used, for checking the connectivity of hosts / How to do it...
  • used, for listing live machines on network / How to do it..., Parallel pings
• ping command, functionalities
  • Round Trip Time (RTT), finding / Round trip time
  • echo packets, limiting / Limiting the number of packets to be sent
  • return status / Return status of the ping command
• pkill command
  • about / The kill family of commands
• popd command
  • about / Getting ready
  • using / How to do it...
  • used, for directory switching / Most frequently used directory switching
• port analysis
  • about / Network traffic and port analysis, How to do it...
• port forwarding
  • about / Port forwarding using SSH
  • SSH, used / Port forwarding using SSH, How to do it...
• POST request
  • about / Posting to a web page and reading the response
• power consumption
  • measuring, powertop command used / Measuring and optimizing power usage
  • optimizing, powertop command used / How to do it...
• powertop command
  • used, for measuring power consumption / Measuring and optimizing power usage, How to do it...
• prepend() function
  • defining / Function to prepend to environment variables
  • working / How it works...
• printf() function / Special variables
• printf command
  • about / How to do it...
• processes
  • about / Gathering information about processes
  • environment variables, displaying for / Showing environment variables for a process
  • killing / Getting ready, How to do it...
• process ID
  • finding / Finding the process ID when given command names
• process manipulation commands
  • top / top
  • ps / Sorting the ps output with respect to a parameter
  • pgrep / Finding the process ID when given command names
• process threads
  • information / Information about process threads
• ps command
  • used, for monitoring CPU usage / Listing the top 10 CPU consuming processes in an hour, How to do it...
  • used, for gathering information about processes / How to do it...
  • about / Sorting the ps output with respect to a parameter
  • TTY filters / TTY filter for ps
• ps output
  • filtering / Filters with ps for real user or ID, effective user or ID
• pushd command
  • about / Getting ready
  • using / How to do it...
  • used, for directory switching / Most frequently used directory switching
• pwd command
  • about / Spawning a separate process with subshell

R

• read command
  • about / Reading n characters without pressing the return key
• readlink command
  • about / How to do it...
• recursive function / The recursive function
• redirection
  • working with / How to do it..., How it works...
  • from file to command / Redirection from a file to a command
  • from text block / Redirecting from a text block enclosed within a script
• referer string
  • about / Setting the referer string with cURL
  • setting, with cURL / Setting the referer string with cURL
• regex
  • about / How to do it...
• regular expressions
  • about / Using regular expressions
  • using / Using regular expressions
  • text matching / How to do it...
  • components / How it works...
  • special characters / Treatment of special characters
  • visualizing / Visualizing regular expressions
• remote disk usage health monitor
  • about / Remote disk usage health monitor
  • working / How it works…
• remote drive
  • mounting, at local mount point / Mounting a remote drive at a local mount point
• remote host
  • commands, executing with SSH / Running commands on a remote host with SSH, How to do it...
• remote machine
  • graphical commands, executing / Running graphical commands on a remote machine
• rename command
  • about / Renaming and moving files in bulk, Getting ready
  • image files, renaming / How to do it...
  • working / How it works…
• return value, of command
  • reading / Reading the return value (status) of a command
• reverse port forwarding
  • about / Reverse port forwarding
• root command
  • about / Filters with ps for real user or ID, effective user or ID
• ROT13 / How it works…
• rotation / Logfile management with logrotate
• Round Trip Time (RTT)
  • about / Round trip time
• routing table
  • information, displaying / Showing routing table information
  • about / Showing routing table information
• RSS feeds
  • parsing / How to do it...
• rsync command
  • used, for backing up snapshots / Backup snapshots with rsync, How to do it...
  • working / How it works...
  • functionalities / There's more...
  • files, excluding while archiving / Excluding files while archiving with rsync
  • non-existent files, deleting / Deleting non-existent files while updating rsync backup
  • backups, scheduling at intervals / Scheduling backups at intervals

S

• #spawn parameter
  • about / Automating with expect
• SCP
  • about / SCP (secure copy program)
  • used, for recursive copying / Recursive copying with SCP
• screenshots
  • taking, from terminal / Taking screenshots from the terminal
• script
  • debugging / Debugging the script, How to do it..., How it works...
• script command
  • about / Getting ready
  • used, for recording terminal sessions / How to do it...
  • working / How it works...
• scripting
  • about / Introduction
• scriptreplay command
  • about / Getting ready
  • used, for recording terminal sessions / How to do it...
  • working / How it works...
• sed command
  • about / How it works..., Using sed to perform text replacement
  • used, for performing text replacement / Using sed to perform text replacement, How to do it…, There's more...
  • blank lines, removing / Removing blank lines
  • text replacement, performing in file / Performing replacement directly in the file
  • matched string notation (&) / Matched string notation (
  • substring match notation (\1) / Substring match notation (\1)
  • multiple expressions combination / Combination of multiple expressions
  • quoting / Quoting
  • used, for replacing matched sentence / Getting ready
• sentence, containing word
  • removing / Removing a sentence in a file containing a word, How to do it...
• services
  • listing / Opened port and services using netstat
• set difference operation, text files
  • about / Getting ready, How it works...
  • performing / How to do it...
• setgid permission / Working with file permissions, ownership, and the sticky bit
• setuid permission / Working with file permissions, ownership, and the sticky bit
• SFTP
  • about / SFTP (Secure FTP)
• SHA-1
  • about / Getting ready, How it works..., How to do it...
• shadow-like salted hash
  • about / How to do it...
• shebang
  • about / Introduction
• shell
  • terminal, printing / Printing in the terminal, How to do it...
  • variables / Playing with variables and environment variables
  • prepend() fucntion, defining / Function to prepend to environment variables, How it works...
  • arithmetic operations / Math with the shell
  • file descriptors / Playing with file descriptors and redirection
  • arrays / Arrays and associative arrays
  • alias / Visiting aliases
  • terminal settings, collecting / Grabbing information about the terminal
  • terminal settings, manipulating / Grabbing information about the terminal
  • dates and time delays, working with / Getting and setting dates and delays
  • script, debugging / Debugging the script
  • functions, defining / Functions and arguments
  • internal field separator (IFS) / Field separators and iterators
• shell scripts
  • about / Introduction
• SHELL variable
  • identifying / Identifying the current shell
• signals
  • about / Killing processes and send or respond to signals
  • responding to / Capturing and responding to signals
  • capturing / Capturing and responding to signals
• sort command
  • about / Sorting unique and duplicates
  • working / How it works…
  • sorting, keys or columns used / Sorting according to the keys or columns
• sort utility / How to do it…
• special variables, awk command
  • NR / Special variables
  • NF / Special variables
  • $0 / Special variables
  • $1 / Special variables
  • $2 / Special variables
• spell checker
  • using / Spell checking and dictionary manipulation
• split command
  • about / Splitting files and data
  • files and data, spiltting / Splitting files and data, How to do it...
  • filename prefix, specifying for spilt files / Specifying a filename prefix for the split files
• squashfs-tools
  • installing / Getting ready
• squashfs files
  • creating / How to do it...
  • mounting / How to do it...
• squashfs filesystem
  • about / Creating filesystems with compression
  • creating, with compression / Creating filesystems with compression
  • customizing / There's more...
  • files, exclusing / Excluding files while creating a squashfs file
• SSH
  • about / Running commands on a remote host with SSH
  • used, for executing commands on remote host / Running commands on a remote host with SSH, How to do it..., There's more...
  • with compression / SSH with compression
  • data, redirecting into stdin of remote shell commands / Redirecting data into stdin of remote host shell commands
  • used, for port forwarding / Port forwarding using SSH, How to do it...
  • non-interactive port forward / Non-interactive port forward
  • reverse port forwarding / Reverse port forwarding
• ssh-keygen command / Getting ready
• SSH keys
  • creating, for auto-login / Password-less auto-login with SSH
• sticky bit permission
  • about / Working with file permissions, ownership, and the sticky bit
• string comparisons
  • performing / How to do it...
• string manipulation functions, awk
  • length(string) / String manipulation functions in awk
  • index() / String manipulation functions in awk
  • split() / String manipulation functions in awk
  • substr() / String manipulation functions in awk
  • sub() / String manipulation functions in awk
  • gsub() / String manipulation functions in awk
  • match() / String manipulation functions in awk
• subshell
  • about / Spawning a separate process with subshell
  • quoting, for preserving spacing and newline character / Subshell quoting to preserve spacing and the newline character
• subshell method / How to do it...
• symbolic links
  • about / Finding symbolic links and their targets
  • handling / How to do it...
  • target path, reading / How to do it...
  • working / How it works...
• syslinux package
  • downloading / Hybrid ISO that boots off a flash drive or hard disk
• syslog
  • about / Logging with syslog
• syslogd
  • used, for logging info from shell script / Logging with syslog, Getting ready, How to do it...
  • about / Logging with syslog
• system information
  • obtaining / Gathering system information, How to do it...

T

• --totals option / Printing total bytes
• tac command / Getting ready
• tail command
  • about / Using head and tail for printing the last or first 10 lines
• Tape ARchives / Archiving with tar
• tar command
  • about / Archiving with tar
  • used, for creating archives / Archiving with tar
  • working / How it works...
  • features / There's more...
  • stdin / stdin and stdout with tar
  • stdout / stdin and stdout with tar
• tar command, features
  • files, appending to archives / Appending files to an archive
  • files and folders, extracting from archives / Extracting files and folders from an archive
  • multiple tar files, concatenating / Concatenating two archives
  • iles, updating with timestamp check / Updating files in an archive with a timestamp check
  • files, comparing in archive and file system / Comparing files in the archive and file system
  • files, deleting from archive / Deleting files from the archive
  • tar archive, compressing / Compression with the tar archive
  • file set, excluding from archiving / Excluding a set of files from archiving
  • version control directories, excluding / Excluding version control directories
  • total bytes, printing / Printing total bytes
• TCP/IP / Introduction
• temporary file
  • creating, mktemp command used / How to do it...
• terminal
  • about / Printing in the terminal
  • printing / How to do it...
  • working / How it works...
  • screenshots, taking from / Taking screenshots from the terminal
• terminal session
  • recording, with script and scriptreplay / How to do it...
• terminal settings
  • collecting / Grabbing information about the terminal, Getting ready
  • manipulating / Getting ready
• tests
  • performing / Comparisons and tests, How to do it...
• text
  • searching, in file with grep command / Searching and mining a text inside a file with grep, How to do it...
  • slicing / Text slicing and parameter operations, How to do it...
• text, between line numbers or patterns
  • printing / Printing text between line numbers or patterns
• time command
  • used, for calculating command execution time / Calculating the execution time for a command, How to do it...
  • working / How it works...
  • parameters / How it works...
• top command
  • about / top
• touch command
  • used, for generating blank files in bulk / Generating blank files in bulk
  • about / Getting ready
• TO_init function / How it works...
• traceroute command / Traceroute
• translate / Translating with tr
• trap command
  • about / Capturing and responding to signals
• tr command
  • about / Translating with tr
  • translation, performing / How to do it...
  • working / How it works…
  • characters, deleting / Deleting characters using tr
  • character set, complementing / Complementing character set
  • characters, squeezing / Squeezing characters with tr
  • character classes / Character classes
• tree command
  • about / Getting ready, How to do it...
• TTY(Tele TYpewriter)
  • about / How to do it...
• TTY filter, for ps command / TTY filter for ps
• Twitter
  • about / Twitter command-line client
  • used, for reading tweets on timeline / Twitter command-line client, Getting ready, How to do it..., How it works...
• TwitterOAuth.sh library / How it works...

U

• --user argument / Accessing pages with HTTP or FTP authentication
• UID value / Checking for super user
• uniq command
  • about / Sorting unique and duplicates, uniq
  • working / How it works…
• Unix time / Getting ready
• until loop / How to do it...
• URLs
  • parsing, from text / Parsing e-mail addresses and URLs from text, How it works...
• usage() function
  • about / How it works…
• user, file permissions
  • about / Working with file permissions, ownership, and the sticky bit
• useradd command
  • about / How it works…
• user administration script
  • about / How to do it…, How it works…
• user agent string
  • setting, with cURL / Setting a user agent string with cURL
• user logins
  • monitoring, for intruder detection / Monitoring user logins to find intruders, How to do it…, How it works…
• usermod command
  • about / How it works…
• user terminals
  • messages, sending to / Sending messages to user terminals, How it works...

V

• var
  • about / How to do it...
• variables
  • about / Playing with variables and environment variables
  • working with / Playing with variables and environment variables, Getting ready, How to do it...
  • environment variables / Playing with variables and environment variables
  • length, finding / Finding the length of a string
  • shell variable, identifying / Identifying the current shell
  • super user, checking / Checking for super user
  • bash prompt string, modifying / Modifying the Bash prompt string (username@hostname:~$)
• version control based backup
  • Git used / Version control-based backup with Git, How to do it...

W

• wall command
  • about / Getting ready
• watch command
  • used, for monitoring command output / Monitoring command outputs with watch
  • differences, highlighting / Highlighting the differences in the watch output
• wc command
  • used, for coutning lines / How to do it...
  • used, for coutning words / How to do it...
  • used, for coutning characters / How to do it...
• Web
  • about / Introduction
• Web backend
  • used, for creating define utility / Creating a "define" utility by using the Web backend, Getting ready, How to do it..., How it works...
• web page
  • downloading, wget command used / Downloading from a web page, How it works...
  • accessing, with HTTP or FTP authentication / Accessing pages with HTTP or FTP authentication
  • downloading, as plain text / Downloading a web page as plain text
  • response, reading / Posting to a web page and reading the response, Getting ready, How it works...
  • posting to / Posting to a web page and reading the response, How it works...
• Web photo album generator
  • about / Web photo album generator, Getting ready
  • working / How it works...
• website
  • data, parsing from / Parsing data from a website
  • broken links, identifying / Finding broken links in a website, How to do it..., How it works...
  • changes, tracking / Tracking changes to a website, How to do it..., How it works...
• WEP (Wired Equivalent Privacy) / How to do it...
• wget command
  • about / Getting ready
  • used, for downloading web page / How to do it...
  • download speed, restricting / Restricting the download speed
  • download, resuming / Resume downloading and continue
  • website, copying / Copying a complete website (mirroring)
• whatis command
  • about / About which, whereis, file, whatis, and load average
• whereis command
  • about / About which, whereis, file, whatis, and load average
• which command
  • about / About which, whereis, file, whatis, and load average
• while loop / How to do it...
  • about / How it works...
• Wi-Fi Protected Access2 (WPA2) / How it works...
• wireless network connection
  • performing / Connecting to a wireless network, How it works...
• word count
  • about / Counting the number of lines, words, and characters in a file
• words
  • about / Getting ready
• words, files
  • counting, wc command used / How to do it...

X

• xargs command
  • about / Playing with xargs
  • using / Getting ready
  • multiple-line input, converting to single-line output / How to do it...
  • single-line intput, converting to multiple-line output / How to do it...
  • working / How it works…
  • formatted arguments, passing / Passing formatted arguments to a command by reading stdin
  • using, with find command / Using xargs with find
  • C program files, counting / Counting the number of lines of C code in a source code directory
  • subshell, using with while loop / While and subshell trick with stdin

Z

• zcat command
  • about / zcat - reading gzipped files without extracting
• zip command
  • about / Archiving and compressing with zip
  • used, for archiving / Archiving and compressing with zip
  • used, for compressing / Archiving and compressing with zip
  • working / How it works...