Index

A

• alias
  • about / Alias
  • creating / Creating alias
  • listing / Listing all aliases
  • removing / Removing an alias
• arithmetic operators / Arithmetic operators
• assignment operator / The assignment operator
• associative array
  • about / The associative array
  • declaration / The declaration and value assignment
  • value assignment / The declaration and value assignment
  • operations / Operations on arrays
• at command
  • used, for executing scripts / Executing scripts using at
• AWK language
  • embedding / Embedding AWK language
  • URL / Embedding AWK language

B

• bash completion
  • managing, with complete / Managing bash completion with complete
  • existing bash completion, viewing / Viewing the existing bash completion
  • default bash completion behavior, modifying / Modifying default bash completion behavior
  • specification, removing / Removing bash completion specification
  • example / An example of bash completion
  • created bash completion, running / Running the created bash completion
• bash startup files
  • using / Using bash startup files
  • .bashrc / .bashrc
  • .bash_profile / .bash_profile
  • .bash_logout / .bash_logout
• basic file operations
  • about / Performing basic file operations
  • files, creating / Creating files
  • files, modifying / Modifying files
  • files, viewing / Viewing files
  • files, deleting / Deleting files
• block device file
  • about / The block device file
  • creating / The block device file
• builtin shell variables
  • defining / Builtin shell variables

C

• cat command
  • about / Filtering based on lines—head and tail
• character based translation
  • tr, using / Character-based translation using tr
  • input characters, deleting / Deleting input characters
  • squeezing, to single occurrence / Squeezing to a single occurrence
  • character set, inverting / Inverting a character set to be translated
• character classes
  • about / Character ranges and classes, Character ranges
  • [*alnum*] / Character ranges
  • [*alpha*] / Character ranges
  • [*digit*] / Character ranges
  • [*lower*] / Character ranges
  • [*upper*] / Character ranges
  • [*blank*] / Character ranges
  • [*graph*] / Character ranges
  • [*print*] / Character ranges
  • [*punct*] / Character ranges
  • [*xdigit*] / Character ranges
  • matching dates, in mm-dd-yyyy format / Matching dates in mm-dd-yyyy format
• character device file
  • about / The block device file
  • creating / The block device file
• character ranges
  • about / Character ranges and classes, Character ranges
  • [a-z] / Character ranges
  • [A-Z] / Character ranges
  • [0-9] / Character ranges
  • [a-zA-Z0-9] / Character ranges
  • [h-k] / Character ranges
  • [2-46-8j-lB-M] / Character ranges
  • regex, for valid shell variable / Regex for a valid shell variable
• command completion
  • about / Command completion
  • bash completion, managing with complete / Managing bash completion with complete
  • bash completion, writing for application / Writing bash completion for your own application
• command line parameters
  • passing, to script / Passing command line parameters to script
  • arguments, reading in script / Reading arguments in scripts
  • command line arguments, shifting / Shifting command line arguments
  • command line options, processing in script / Processing command line options in a script
• commands
  • scheduling / Scheduling commands
• Common UNIX Printing System (CUPS)
  • about / Socket file
• comparison operators / Comparison operators
• conditional statements
  • using, with if and else / Using conditional statements with if and else, Simple if and else
  • elif statement / The if, elif, and else statements
  • if statement / The if, elif, and else statements
  • else statement / The if, elif, and else statements
  • nested if / Nested if
• configuration files
  • about / Configuration files
  • viewing / Viewing and modifying configuration files
  • modifying / Viewing and modifying configuration files
• construct commands
  • defining, eval used / Construct commands using eval
• cron configuration / Cron configuration
• cron daemon / Cron daemon
• Cron jobs
  • defining / Cron jobs
  • cron daemon / Cron daemon
  • cron configuration / Cron configuration
  • crontab entries / Crontab entries
• crontab entries
  • writing / Crontab entries
  • special strings / Special strings in Crontab
  • managing / Managing the crontab entry
  • listing / Listing crontab entries
  • editing / Editing crontab entries
  • removing / Removing crontab entries
• cut-based selection
  • about / The Cut-based selection, Cutting across columns
  • text selection, in files / Text selection in files
• cut command, options
  • -b LIST / The Cut-based selection
  • -c LIST / The Cut-based selection
  • -d DELIM / The Cut-based selection
  • -f LIST / The Cut-based selection
  • --complement / The Cut-based selection
  • -s / The Cut-based selection
  • --output-delimiter=STRING / The Cut-based selection

D

• debugging, scripts
  • performing / Debugging your scripts
  • echo command used / Debugging using echo
  • entire script, debugging with -x option / Debugging an entire script using -x
  • section, debugging with set options / Debugging sections of a script using the set options
• default environment
  • defining / Knowing the default environment
• default history behavior
  • modifying / Modifying the default history behavior
• diff command
  • options / Files comparison using diff
• directory file
  • about / Directory file

E

• /etc/passwd
  • URL / Embedding AWK language
• environment variables
  • versus shell variables / Differences between shell and environment variables
  • about / Differences between shell and environment variables
• exit codes
  • about / Exit codes
  • with special meaning / Exit codes with a special meaning
  • Exit code 0 / Exit codes with a special meaning
  • Exit code 1 / Exit codes with a special meaning
  • Exit code 2 / Exit codes with a special meaning
  • Exit code 126 / Exit codes with a special meaning
  • Exit code 127 / Exit codes with a special meaning
  • Exit code 128+n / Exit codes with a special meaning
• expressions, testing with test command
  • about / Testing expressions with a test
  • file checks / File checks
  • arithmetic checks / Arithmetic checks
  • string checks / String checks
  • expression checks / Expression checks

F

• files
  • creating / Creating files
  • directory file / Directory file
  • regular file / Regular file
  • viewing / Viewing files
  • viewing, ls command used / Viewing files
  • content, viewing with cat command / Viewing content using cat
  • viewing, more command used / more and less
  • viewing, less command used / more and less
  • deleting / Deleting files
  • regular file, deleting / Deleting a regular file
  • directory, deleting / Deleting a directory
  • copying / Moving and copying files, Copying files
  • moving / Moving files
  • directory, moving to new location / Moving a directory to a new location
  • renaming / Renaming a file
  • copying locally / Copying files locally
  • copying, to another location / Copying a file to another location
  • copying remotely, scp command used / Copying files remotely
  • copying, to remote server / Copying files to a remote server
  • comparing / Comparing files
  • comparing, diff command used / Files comparison using diff, Example
  • searching / Finding files
  • searching, according to usecase / Searching files according to use case
  • finding and deleting, based on inode number / Finding and deleting a file based on inode number
  • link, creating / Links to a file
  • special files / Special files
  • temporary files / Temporary files
  • permissions / Permission and ownership
  • ownership / Permission and ownership
  • opened files list, obtaining / Getting the list of open files
  • configuration files / Configuration files
• fle descriptors
  • about / File descriptors
• for loop
  • about / Looping around with for
  • simple iteration / Simple iteration
  • command output, iterating over / Iterating over a command output
  • range, specifying / Specifying a range to the for loop
• format modifiers
  • defining / Interacting with shell
• format specification
  • used, for printing different data type format / Interacting with shell
• functions
  • using / Using functions and positional parameters
  • calling in bash / Calling a function in bash
  • parameters, passing to / Passing parameters to functions

G

• grep command
  • used, for filtering output / Filtering an output using grep
  • syntax / Syntax, Looking for a pattern in a file
  • uses / A few more grep usages
  • searching, in a binary file / Searching in a binary file
  • searching, in a directory / Searching in a directory
  • files/directories, excluding from search / Excluding files/directories from a search
  • filename, displaying with matching pattern / Display a filename with a matching pattern
  • exact word, matching / Matching an exact word
  • output, editing with sed command / Editing output using sed, String substitution using s
  • multiple substitutions / Multiple substitutions
• grep command, options
  • -i / Syntax
  • -v / Syntax
  • -o / Syntax
  • -f FILE / Syntax
  • -e PATTERN / Syntax
  • -E / Syntax
  • -r / Syntax
  • -R / Syntax
  • -a / Syntax
  • -n / Syntax
  • -q / Syntax
  • s / Syntax
  • -c / Syntax
  • -A NUM / Syntax
  • -B NUM / Syntax
  • -C NUM / Syntax
  • pattern, searching in multiple files / Looking for a pattern in multiple files

H

• head command
  • about / Filtering based on lines—head and tail
  • used, for printing lines / Printing lines using head, Printing the first few bytes, Checking log entries
  • used, for finding lines / Finding any line in a file
• head command, options
  • -c [-] K / Printing lines using head
  • -n [-]K / Printing lines using head
  • -q / Printing lines using head
  • -v / Printing lines using head
• Hello world
  • defining, in shell / Hello World in shell
  • interacting, with shell / Interacting with shell
  • bash script file, creating / Let's make it scripted
• history, shell
  • defining / Knowing your history
  • shortcuts / Handy shortcuts for seeing the history
• history builtin command
  • about / The history builtin command
• history shell builtin command
  • defining / The history builtin command

I

• indexed array
  • about / Indexed arrays
  • array declaration / Array declaration and value assignment
  • value assignment / Array declaration and value assignment
  • operations / Operations on arrays
• init-based system
  • URL / systemd
• input text
  • sorting / Sorting an input text
  • single file, sorting / Sorting a single file
  • multiple files, sorting / Sorting a single file
  • output, redirecting to sort / Redirecting output to sort
• inter-process communication
  • about / Inter-process communication
  • named pipes / Inter-process communication
  • shared memory / Inter-process communication
  • message queue / Inter-process communication
  • semaphores / Inter-process communication
  • information about IPC, ipcs command used / Information on IPC using ipcs
  • information, listing / Listing information provided by IPCs
  • PID of processes, knowing / Knowing processes' PID who recently did IPCs

K

• killall command / Using the killall command
• kill command / Using the kill command

L

• languages
  • embedding / Embedding languages
• links, between files
  • soft link / Soft link
  • hard link / Hard link
  • hard link, versus soft link / Difference between hard link and soft link
• logical operators / Logical operators

M

• matching dates
  • valid month, matching / Matching a valid month
  • valid day, matching / Matching a valid day
  • valid year in date, matching / Matching the valid year in a date
  • valid months, combining with days and regex / Combining valid months, days, and years regex to form valid dates
• metacharacters, regular expression
  • about / Regular expression metacharacters
  • * (Asterisk) / Regular expression metacharacters
  • + (Plus) / Regular expression metacharacters
  • ? / Regular expression metacharacters
  • . (Dot) / Regular expression metacharacters
  • ^ / Regular expression metacharacters
  • $ / Regular expression metacharacters
  • [... ] / Regular expression metacharacters
  • [^... ] / Regular expression metacharacters
  • | (Bar) / Regular expression metacharacters
  • {X} / Regular expression metacharacters
  • {X,Y} / Regular expression metacharacters
  • (...) / Regular expression metacharacters
  • < / Regular expression metacharacters
  • > / Regular expression metacharacters
  • / Regular expression metacharacters

N

• named pipe file
  • about / Named pipe file
  • creating / Named pipe file
• nice command / Using nice

O

• opened files
  • list, obtaining / Getting the list of open files
  • files opened by specific application, listing / Knowing the files opened by a specific application
  • applications, listing / Listing the applications that opened a file
  • files opened by specific user, listing / Knowing the files opened by a user
• operators
  • defining / Operators
  • assignment operator / The assignment operator
  • arithmetic operators / Arithmetic operators
  • logical operators / Logical operators
  • comparison operators / Comparison operators
  • >> / Redirecting the standard I/O and error streams
  • < / Redirecting the standard I/O and error streams
  • >& / Redirecting the standard I/O and error streams
  • >>& / Redirecting the standard I/O and error streams
  • | / Redirecting the standard I/O and error streams
• options, at command
  • -f FILE / Executing scripts using at
  • -l / Executing scripts using at
  • -m / Executing scripts using at
  • -M / Executing scripts using at
  • -r / Executing scripts using at
  • -t time / Executing scripts using at
  • -c job_number / Executing scripts using at
  • -v / Executing scripts using at
• options, crontab
  • -u user / Managing the crontab entry
  • -l / Managing the crontab entry
  • -e / Managing the crontab entry
  • -r / Managing the crontab entry
  • -i / Managing the crontab entry
• ownership, files
  • about / Permission and ownership
  • viewing / Viewing the ownership and permission of files
  • owner, changing / Changing the owner and group, Changing a file's owner
  • group ownership, changing / Changing group ownership

P

• parameters
  • passing, to functions / Passing parameters to functions
• permissions, files
  • about / Permission and ownership
  • viewing / Viewing the ownership and permission of files
  • changing / Changing permission
• pipe
  • about / Pipe
• pipeline
  • about / Pipe and pipelines – connecting commands, Pipeline
• popd command
  • about / pushd and popd
• positional parameters
  • using / Using functions and positional parameters
• POSIX (Portable Operating System Interface) / Exit codes
• processes
  • listing / Listing and monitoring processes
  • monitoring / Monitoring processes
• processes, listing
  • about / Listing processes
  • syntax / Syntax
  • simple process selection / Simple process selection
  • process selection by list / Process selection by list
  • output format control / Output format control
  • processes with details / Listing all processes with details
  • processes run by user / Listing all processes run by a user
  • processes running in current terminal / Processes running in the current terminal
  • processes by command name / Listing processes by a command name
  • tree format display / Tree format display of processes
• Process ID (PID) / Knowing the files opened by a specific application
• process management
  • about / Process management
  • process, creating / Process creation and execution
  • process, executing / Process creation and execution
  • process, terminating / Process termination
• process scheduling priorities
  • about / Process scheduling priorities
  • changing / Changing scheduling priorities
  • changing, nice command used / Using nice
  • changing, renice command used / Using renice
• process substitution
  • about / Process substitution
  • output of two processes, comparing / Diffing the output of two processes
• process termination
  • performing / Process termination
  • kill command, used / Using the kill command
  • killall command, used / Using the killall command, Using the pkill command
• pstree command / Tree format display of processes
• pushd command
  • about / pushd and popd
• Python
  • URL / Embedding Python language
• Python languages
  • embedding / Embedding Python language

R

• ranges
  • N / The Cut-based selection
  • N- / The Cut-based selection
  • N-M / The Cut-based selection
  • -M / The Cut-based selection
• regular expression
  • about / Regular expressions
  • metacharacters / Regular expression metacharacters
  • classes / Character ranges and classes, Character ranges
  • character ranges / Character ranges
  • creating / Character ranges
  • URL / Combining valid months, days, and years regex to form valid dates
• regular file
  • about / Regular file
  • touch command / Touch command
  • command line editors, using / Using the command line editors
  • cat command, using / Using the cat command
  • command output, redirecting / Redirecting the command's output
• renice command / Using renice
• resolution path, symbolic link
  • enabling / Enabling/disabling symbolic link's resolution path
  • disabling / Enabling/disabling symbolic link's resolution path

S

• scheduled tasks
  • listing / Listing scheduled tasks
  • removing / Removing scheduled tasks
• scp command
  • options / Copying files remotely
• script file
  • scheduling / Scheduling a script file
• scripts
  • exiting from / Exiting from scripts and exit codes
  • with exit codes / Script with exit codes
  • modularizing / Modularizing your scripts
  • source / Source to a script file
  • debugging / Debugging your scripts
  • executing, at command used / Executing scripts using at
• sed command, flags
  • g / String substitution using s
  • p / String substitution using s
  • w filename / String substitution using s
  • N / String substitution using s
• sed command, options
  • -n / Editing output using sed
  • -e script / Editing output using sed
  • -r / Editing output using sed
  • -l N / Editing output using sed
  • --posix / Editing output using sed
  • -u / Editing output using sed
• select loop
  • using / Loop using select
• services
  • managing / Managing services
  • status / Status of a service
  • enabling / Enabling and disabling services
  • disabling / Enabling and disabling services
  • starting / Start and stop a service
  • stopping / Start and stop a service
• set command
  • using / Make bash behave using set
  • exit, on first failure / Exit on the first failure
• SETs / Character-based translation using tr
• shared library
  • URL / .bashrc
• shell environment
  • viewing / Viewing a shell environment
  • printenv / printenv
  • env / env
  • modifying / Modifying a shell environment
  • environment variables, creating / Creating environment variables
  • environment variables, modifying / Modifying environment variables
  • environment variables, deleting / Deleting environment variables
• shell expansions
  • defining / Shell expansions
  • ~ (Tilde) / ~ (Tilde)
  • * (Asterisk) / * (Asterisk)
  • ? (Question mark) / ? (Question mark)
  • [ ] (Square brackets) / [ ] (Square brackets)
  • { } (Curly brackets) / { } (Curly brackets)
• shell script library
  • creating / Creating a shell script library
  • loading / Loading a shell script library
  • calling in bash / Calling a shell library in bash
  • calling, in another shell script / Calling shell library in another shell script
• shell variables
  • used, in bash shell / Builtin shell variables
  • versus environment variables / Differences between shell and environment variables
  • about / Differences between shell and environment variables
  • used, for controlling history / Shell variables controlling the history
• shell variables, bash shell
  • BASH / Builtin shell variables
  • BASH_VERSION / Builtin shell variables
  • BASHPID / Builtin shell variables
  • EUID / Builtin shell variables
  • HOME / Builtin shell variables
  • HOSTNAME / Builtin shell variables
  • PATH / Builtin shell variables
  • PPID / Builtin shell variables
  • PWD / Builtin shell variables
• shortcuts, shell
  • defining / Handy shortcuts for seeing the history
  • [Ctrl + r] / [Ctrl + r]
  • up and down arrow key / Up and down arrow key
  • !! / !!
  • !(search_string) / !(search_string)
  • !?(search_string) / !?(search_string)
• signals
  • about / Signals
  • frequently used signals / Available signals
  • Default action section / Available signals
• socket file
  • about / Socket file
• sort command, options
  • -b / Sorting an input text
  • -d / Sorting an input text
  • -f / Sorting an input text
  • -i / Sorting an input text
  • -M / Sorting an input text
  • -n / Sorting an input text
  • -r / Sorting an input text
  • -h / Sorting an input text
  • -u / Sorting an input text
  • -o file / Sorting an input text
  • -m / Sorting an input text
  • -k n / Sorting an input text
• source
  • about / Source to a script file
  • syntax / Syntax
• special files
  • about / Special files
  • block device file / The block device file
  • character device file / The block device file
  • named pipe file / Named pipe file
  • socket file / Socket file
• standard I/O and error streams
  • about / Standard I/O and error streams
  • stdin file / Standard I/O and error streams
  • stdout file / Standard I/O and error streams
  • stderr file / Standard I/O and error streams
  • file descriptors / File descriptors
  • redirecting / Redirecting the standard I/O and error streams, Redirecting standard output
  • standard input, redirecting / Redirecting standard input
  • standard error, redirecting / Redirecting standard errors, Multiple redirection
• stdout
  • passing as parameter, xargs used / Passing stdout as a parameter using xargs
• stream
  • duplicating, with tee command / Duplicating a stream using tee
  • output, writing, to stdout / Writing an output to stdout and appending to a file
  • appending, to file / Writing an output to stdout and appending to a file
  • output, sending to multiple commands / Sending an output to multiple commands
• switch
  • about / Switch to my choice
  • syntax / Switch to my choice
• systemd
  • defining / systemd
  • unit files, defining / systemd units
• system logs
  • viewing / Viewing system logs
  • latest log entries, viewing / Viewing the latest log entries
  • particular time interval logs, viewing / Viewing logs of a particular time interval

T

• tail command
  • about / Filtering based on lines—head and tail
• tail command, options
  • -c [+]K / Printing lines using tail
  • -n [+]K / Printing lines using tail
  • -f [{name|descriptor}] / Printing lines using tail
  • --retry / Printing lines using tail
  • --max-unchanged-stats=N / Printing lines using tail
  • --pid=PID / Printing lines using tail
  • -q / Printing lines using tail
  • -F / Printing lines using tail
  • -s N / Printing lines using tail
  • -v / Printing lines using tail
• task management
  • defining / Task management
  • tasks, running in background / Running tasks in the background
  • running task, sending to background / Sending a running task to the background
  • background tasks, listing / Listing background tasks
  • tasks, moving to foreground / Moving tasks to the foreground
  • tasks, terminating / Terminating tasks
• tasks
  • running, at specific time / Running tasks at a specific time
• tee command
  • used, for duplicating stream / Duplicating a stream using tee
• tee command, options
  • -a, --append / Duplicating a stream using tee
  • -i, --ignore- / Duplicating a stream using tee
• temporary files
  • about / Temporary files
  • creating, mktemp used / Creating a temporary file using mktemp
• traps
  • about / Traps
• tr command
  • used, for character based translation / Character-based translation using tr
• tr commands, options
  • -c / Character-based translation using tr
  • -C / Character-based translation using tr
  • -d / Character-based translation using tr
  • -s / Character-based translation using tr
  • -t / Character-based translation using tr

U

• uniq command, options
  • -c / Filtering unique elements
  • -d / Filtering unique elements
  • -f N / Filtering unique elements
  • -i / Filtering unique elements
  • -u / Filtering unique elements
  • -s N / Filtering unique elements
  • -w N / Filtering unique elements
• unique text
  • sorting / Sorting and finding unique text
  • finding / Sorting and finding unique text
  • input text, sorting / Sorting an input text
  • unique elements, filtering / Filtering unique elements, Unique elements in a file
• unit files
  • defining / systemd units
• until loop
  • about / The until loop
  • using / The until loop

V

• variables
  • defining / Define variables of choice
  • nomenclature / Nomenclature
  • value, assigning / Assigning a value
  • value, accessing / Accessing a value
  • constant variables / Constant variables
  • reading, from user input / Reading variables from a user input
  • setting / Setting/unsetting variables
  • unsetting / Setting/unsetting variables
• vim
  • reference link / Using the command line editors

W

• while loop
  • about / The while loop
  • using / The while loop

X

• xargs command
  • about / Passing stdout as a parameter using xargs
  • syntax / Passing stdout as a parameter using xargs
  • basic operations / Basic operations with xargs
  • for finding file with maximum size / Using xargs to find a file with the maximum size
  • files, archiving with given pattern / Archiving files with a given pattern