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149${var:-default} for fallback values
150${var:=default} assigning defaults
151${var:?message} failing on unset
152${var:+alt} conditional substitution
153Colon versus no-colon forms of expansion tests
154${#var} string length
155${var:offset} substring from offset
156${var:offset:length} substring slicing
157Negative offsets in substring expansion
158${var#pattern} shortest prefix removal
159${var##pattern} longest prefix removal
160${var%pattern} shortest suffix removal
161${var%%pattern} longest suffix removal
162${var/pat/rep} first match replacement
163${var//pat/rep} global replacement
164${var/#pat/rep} anchored at start
165${var/%pat/rep} anchored at end
166${var^} uppercase first character
167${var^^} uppercase all
168${var,} lowercase first character
169${var,,} lowercase all
170${var~~} toggling case
171${!var} indirect expansion
172${!prefix*} listing variable names
173${var@Q} quoting for reuse
174${var@E} escape expansion
175${var@P} prompt expansion
176${var@A} assignment form
177${var@a} attribute flags
178${var@U} and @L case operators
179Parameter expansion on positional parameters
180Parameter expansion applied to arrays
181Basename and dirname via expansion
182Extracting file extensions with expansion
183Trimming whitespace with expansion
184Nested expansion limits
185Pattern characters inside expansion
186Using extglob inside expansion
187Expansion order in bash
188Why quoting expansions matters
189Shell variables versus environment variables
190export and the environment
191declare attributes overview
192declare -i integer variables
193declare -r readonly variables
194declare -x exported variables
195declare -l and -u case-forcing variables
196declare -n nameref variables
197declare -g globals inside functions
198local variables in functions
199Dynamic scoping in bash
200unset on variables and functions
201readonly and its pitfalls
202Special variable $$ process ID
203Special variable $! last background PID
204Special variable $? exit status
205Special variable $- shell flags
206Special variable $_ last argument
207$0 and script names
208$# argument count
209$* versus $@
210"$@" versus "$*" quoting
211IFS and word splitting
212Changing IFS temporarily
213RANDOM and SRANDOM
214SECONDS as a timer
215LINENO and debugging
216BASH_SOURCE and script location
217FUNCNAME and call stacks
218BASH_COMMAND
219BASH_REMATCH
220PIPESTATUS array
221PS1 through PS4
222PROMPT_COMMAND
223HISTFILE and history variables
224HISTCONTROL and HISTIGNORE
225TMOUT idle timeout
226CDPATH
227OLDPWD and cd -
228EPOCHSECONDS and EPOCHREALTIME
229BASH_VERSINFO
230SHLVL
231COLUMNS and LINES
232MAPFILE default array
233REPLY default variable
234PATH search order
235hash and the command cache
236Environment for a single command
237env -i for clean environments
238printenv and env differences
239Declaring indexed arrays
240Compound array assignment
241Appending with +=
242Reading elements and ${arr[@]}
243${#arr[@]} array length
244${!arr[@]} listing indices
245Array slicing
246Sparse arrays
247Unsetting elements
248Copying arrays
249Passing arrays to functions
250Returning arrays from functions
251Arrays and quoting of elements
252mapfile and readarray
253mapfile -t and -d options
254mapfile callbacks with -C
255Reading lines into arrays safely
256Splitting strings into arrays
257Joining arrays with IFS
258Sorting arrays
259Deduplicating arrays
260Filtering arrays
261Reversing arrays
262Searching arrays
263Arrays of arrays workaround
264Declaring associative arrays
265Associative array keys and values
266Iterating over associative arrays
267Testing key existence with -v
268Counting words with associative arrays
269Associative arrays as sets
270Associative arrays as lookup tables
271Namerefs with arrays
272Positional parameters as arrays
273set -- to reassign parameters
274shift and shift N
275Stack and queue implementations
276Matrix emulation in bash
277Array performance considerations
278Arrays versus delimited strings
279Single quotes
280Double quotes
281Backslash escaping
282ANSI-C quoting with $'...'
283Locale translation with $"..."
284Quote removal
285Order of shell expansions
286Tilde expansion forms
287Brace expansion lists
288Brace expansion ranges
289Brace expansion with zero padding
290Brace expansion with steps
291Nested brace expansion
292Brace expansion versus variables
293Cartesian products with braces
294Command substitution with $()
295Backticks versus $()
296Nested command substitution
297Arithmetic expansion $(( ))
298Arithmetic operators in bash
299Bitwise operators in arithmetic
300Ternary in arithmetic
301Base conversion in arithmetic
302let and (( )) commands
303Integer overflow in bash arithmetic
304Floating point with bc
305Floating point with awk
306Word splitting rules
307Filename expansion rules
308Process substitution <( )
309Process substitution >( )
310Process substitution versus pipes
311Using process substitution with diff
312Using process substitution with comm
313Using process substitution with while read
314Quoting for eval
315Why eval is dangerous
316printf %q for safe quoting
317Quoting in aliases
318Quoting in ssh remote commands
319Quoting in xargs and find -exec
320The * wildcard
321The ? wildcard
322Bracket expressions
323Character classes like [:alpha:]
324Negated brackets with [!...]
325Globs and hidden files
326dotglob option
327nullglob option
328failglob option
329nocaseglob option
330globstar and **
331extglob ?(pattern)
332extglob *(pattern)
333extglob +(pattern)
334extglob @(pattern)
335extglob !(pattern)
336GLOBIGNORE variable
337globskipdots option
338Glob sort order and locale
339Globs versus regular expressions
340When a glob matches nothing
341Globs in [[ ]] comparisons
342Globs in case patterns
343Globbing with very long lists
344ARG_MAX and glob limits
345Quoting globs to pass literally
346set -f to disable globbing
347Globbing and spaces in names
348Globbing in scripts safely
349File descriptors 0 1 and 2
350Redirecting stdout with >
351Appending with >>
352Redirecting stderr with 2>
353Merging with 2>&1
354The &> and &>> shortcuts
355Order of redirections matters
356Redirecting input with <
357Duplicating descriptors with n>&m
358Closing descriptors with n>&-
359Opening custom descriptors with exec
360Reading and writing with <>
361noclobber and >
362Here-documents basics
363Quoted here-document delimiters
364Indented here-documents with <<-
365Here-documents with variable expansion
366Here-documents feeding ssh
367Here-documents feeding cat to files
368Here-documents inside functions
369Here-strings with <<<
370Here-strings with read
371Redirecting a whole block
372Redirecting a whole script with exec
373Logging stdout and stderr to a file
374Swapping stdout and stderr
375tee for splitting output
376tee -a and process substitution
377/dev/null /dev/zero and /dev/full
378/dev/stdin /dev/stdout /dev/stderr
379/dev/tcp and /dev/udp pseudo-paths
380Named pipes with mkfifo
381Pipes and SIGPIPE
382Pipe buffering and stdbuf
383Pipelines and subshells
384lastpipe option
385pipefail option
386Capturing stderr into a variable
387Reading a file descriptor with read -u
388Temporary files with mktemp
389Cleaning temp files with traps
390if elif else chains
391Exit status as truth
392The test builtin
393[ ] versus [[ ]]
394String tests in [[ ]]
395Numeric tests -eq -lt and friends
396File tests -e -f -d -r -w -x
397File tests -s -L -nt -ot
398Regex matching with =~
399Capturing groups with BASH_REMATCH
400Storing regexes in variables
401Short-circuit AND and OR lists
402The conditional-list fallback trap
403Grouping with { } and ( )
404Subshell versus brace group
405Negation with !
406case with multiple patterns
407case fall-through with ;& and ;;&
408while loops
409until loops
410for in lists
411C-style for loops
412select menus
413break and continue with levels
414Infinite loops and exit conditions
415Reading files with while read -r
416Preserving whitespace with IFS= read
417Reading NUL-delimited input
418Loop over command output safely
419Loop over find results safely
420Looping over ranges
421Looping with seq
422Loop performance considerations
423Early exit patterns
424Retry loops with backoff
425Polling loops with timeouts
426Menu-driven scripts
427Looping over words in strings
428Looping over associative keys
429Looping over file lines in parallel
430Defining functions two ways
431Function arguments and positional params
432Function return codes
433Returning values by stdout
434Returning values with namerefs
435Local variables and recursion
436Recursion in bash
437Function overriding builtins with command
438command -v versus which
439type and type -a
440builtin command
441declare -f to print functions
442export -f for subshells
443Functions versus aliases
444Alias expansion rules
445unalias and alias scope
446source and the . builtin
447Sourcing with arguments
448Source guards and idempotence
449Library files for shell code
450Detecting sourced versus executed
451Namespacing function names
452Function tracing with declare -t
453Function tracing with trap RETURN
454Default arguments in functions
455Option parsing in functions
456Variadic functions
457Higher-order function patterns
458Callbacks in bash
459Memoization in bash
460Unit testing functions
461bats framework basics
462shellcheck usage
463shellcheck common warnings
464shfmt formatting
465Writing portable POSIX sh
466Bashisms to avoid
467dash versus bash
468Posix mode in bash
469Compatibility across bash versions
470trap basics
471Trapping EXIT
472Trapping ERR
473Trapping INT and TERM
474Trapping HUP for reload
475Trapping DEBUG
476Trapping RETURN
477Listing traps with trap -p
478Resetting traps
479Ignoring signals with trap ''
480Trap inheritance in subshells
481errtrace option
482Cleaning up temp files via EXIT
483Lockfiles with traps
484Graceful shutdown of loops
485Forwarding signals to child processes
486Waiting for children with wait
487wait -n for first finisher
488wait with PIDs and status
489Signal handling while in wait
490Traps and sleep interruptions
491Traps in functions
492Exit codes from signals 128+N
493Error handling strategies
494set -e behavior details
495set -e pitfalls in conditionals
496set -u and unset arrays
497set -o pipefail interactions
498inherit_errexit option
499Writing die and warn helpers
500Stack traces on error
501Retrying commands
502Timeouts with timeout command
503Idempotent scripts
504Jobs table and %N specs
505Backgrounding with &
506Suspending with Ctrl-Z
507fg and bg
508jobs -l and -p
509disown -h and -a
510Job control in scripts
511set -m monitor mode
512Process groups and sessions
513Controlling terminal
514wait for background jobs
515Parallelism with xargs -P
516Parallelism with background loops
517Limiting concurrency in bash
518GNU parallel basics
519parallel with ::: and :::+
520parallel --pipe
521parallel --jobs and --load
522parallel --joblog and --resume
523Semaphores with mkfifo
524Semaphores with flock
525The coproc keyword
526Named coprocs
527Talking to a coproc
528Closing coproc descriptors
529Coprocs versus named pipes
530Co-processes for bc
531Subshells and ( )
532Background subshells
533Command groups in pipelines
534Process substitution and wait
535Detaching with setsid
536Detaching with nohup
537Running under screen
538Running under tmux
539tmux sessions windows and panes
540tmux copy mode and scripting
541tmux config and plugins
542screen basics and detach
543Surviving logout reliably
544Readline basics
545Emacs mode key bindings
546Vi mode in readline
547.inputrc configuration
548bind command
549Custom key bindings
550Reverse search with Ctrl-R
551History expansion with !!
552History designators !$ !^ !*
553History modifiers :h :t :r :e
554Quick substitution ^old^new
555fc command
556history -a -n -r
557Shared history across terminals
558Programmable completion basics
559complete -F functions
560complete -W word lists
561compgen
562bash-completion package
563Writing a completion script
564Completion for subcommands
565Prompt customization PS1
566Prompt escape sequences
567Colors in prompts with tput
568Git branch in prompt
569Multi-line prompts
570Startup files overview
571.bashrc versus .bash_profile
572.profile and login shells
573/etc/profile and /etc/profile.d
574.bash_logout
575Interactive versus non-interactive shells
576Login versus non-login shells
577shopt options list
578checkwinsize and autocd
579cdspell and dirspell
580histappend and cmdhist
581pushd popd dirs
582Directory stack tricks
583Aliases for productivity
584Functions for productivity
585zsh differences overview
586fish differences overview
587Choosing a shell
588Dotfile management with git
589Dotfile management with stow
590Script skeleton template
591Usage and help text
592getopts basics
593getopts with optional arguments
594Long options with getopt
595Long options by case loops
596Parsing subcommands
597Validating arguments
598Argument defaults via expansion
599Reading config files
600Parsing key=value files safely
601Parsing INI files
602Parsing JSON with jq
603jq filters and pipes
604jq select map and reduce
605jq raw output and arguments
606Parsing YAML with yq
607Parsing CSV in bash
608Parsing XML with xmllint
609Parsing HTML basics
610Colored output with ANSI codes
611Detecting terminals with -t
612Progress bars in bash
613Spinners in bash
614Logging functions
615Log levels and timestamps
616Date arithmetic in bash
617Date formatting with date
618Parsing dates with date -d
619Random strings and passwords
620UUIDs from the shell
621Hashing in scripts
622Base64 in scripts
623URL encoding in bash
624Lockfiles and single instance
625PID files
626Daemonizing a script
627Running as root checks
628Self-updating scripts
629Script directory resolution
630Symlink resolution with readlink -f
631Safe temporary directories
632Atomic file writes
633Atomic directory swaps
634Checking dependencies
635Portable shebangs with env
636Exit code conventions
637Man page for your script
638Packaging scripts as deb
639Embedding binaries in scripts with makeself
640Performance profiling of scripts
641Avoiding subshell forks
642Avoiding useless cat
643Bash versus Python decision

149${var:-default} for fallback values
150${var:=default} assigning defaults
151${var:?message} failing on unset
152${var:+alt} conditional substitution
153Colon versus no-colon forms of expansion tests
154${#var} string length
155${var:offset} substring from offset
156${var:offset:length} substring slicing
157Negative offsets in substring expansion
158${var#pattern} shortest prefix removal
159${var##pattern} longest prefix removal
160${var%pattern} shortest suffix removal
161${var%%pattern} longest suffix removal
162${var/pat/rep} first match replacement
163${var//pat/rep} global replacement
164${var/#pat/rep} anchored at start
165${var/%pat/rep} anchored at end
166${var^} uppercase first character
167${var^^} uppercase all
168${var,} lowercase first character
169${var,,} lowercase all
170${var~~} toggling case
171${!var} indirect expansion
172${!prefix*} listing variable names
173${var@Q} quoting for reuse
174${var@E} escape expansion
175${var@P} prompt expansion
176${var@A} assignment form
177${var@a} attribute flags
178${var@U} and @L case operators
179Parameter expansion on positional parameters
180Parameter expansion applied to arrays
181Basename and dirname via expansion
182Extracting file extensions with expansion
183Trimming whitespace with expansion
184Nested expansion limits
185Pattern characters inside expansion
186Using extglob inside expansion
187Expansion order in bash
188Why quoting expansions matters
189Shell variables versus environment variables
190export and the environment
191declare attributes overview
192declare -i integer variables
193declare -r readonly variables
194declare -x exported variables
195declare -l and -u case-forcing variables
196declare -n nameref variables
197declare -g globals inside functions
198local variables in functions
199Dynamic scoping in bash
200unset on variables and functions
201readonly and its pitfalls
202Special variable $$ process ID
203Special variable $! last background PID
204Special variable $? exit status
205Special variable $- shell flags
206Special variable $_ last argument
207$0 and script names
208$# argument count
209$* versus $@
210"$@" versus "$*" quoting
211IFS and word splitting
212Changing IFS temporarily
213RANDOM and SRANDOM
214SECONDS as a timer
215LINENO and debugging
216BASH_SOURCE and script location
217FUNCNAME and call stacks
218BASH_COMMAND
219BASH_REMATCH
220PIPESTATUS array
221PS1 through PS4
222PROMPT_COMMAND
223HISTFILE and history variables
224HISTCONTROL and HISTIGNORE
225TMOUT idle timeout
226CDPATH
227OLDPWD and cd -
228EPOCHSECONDS and EPOCHREALTIME
229BASH_VERSINFO
230SHLVL
231COLUMNS and LINES
232MAPFILE default array
233REPLY default variable
234PATH search order
235hash and the command cache
236Environment for a single command
237env -i for clean environments
238printenv and env differences
239Declaring indexed arrays
240Compound array assignment
241Appending with +=
242Reading elements and ${arr[@]}
243${#arr[@]} array length
244${!arr[@]} listing indices
245Array slicing
246Sparse arrays
247Unsetting elements
248Copying arrays
249Passing arrays to functions
250Returning arrays from functions
251Arrays and quoting of elements
252mapfile and readarray
253mapfile -t and -d options
254mapfile callbacks with -C
255Reading lines into arrays safely
256Splitting strings into arrays
257Joining arrays with IFS
258Sorting arrays
259Deduplicating arrays
260Filtering arrays
261Reversing arrays
262Searching arrays
263Arrays of arrays workaround
264Declaring associative arrays
265Associative array keys and values
266Iterating over associative arrays
267Testing key existence with -v
268Counting words with associative arrays
269Associative arrays as sets
270Associative arrays as lookup tables
271Namerefs with arrays
272Positional parameters as arrays
273set -- to reassign parameters
274shift and shift N
275Stack and queue implementations
276Matrix emulation in bash
277Array performance considerations
278Arrays versus delimited strings
279Single quotes
280Double quotes
281Backslash escaping
282ANSI-C quoting with $'...'
283Locale translation with $"..."
284Quote removal
285Order of shell expansions
286Tilde expansion forms
287Brace expansion lists
288Brace expansion ranges
289Brace expansion with zero padding
290Brace expansion with steps
291Nested brace expansion
292Brace expansion versus variables
293Cartesian products with braces
294Command substitution with $()
295Backticks versus $()
296Nested command substitution
297Arithmetic expansion $(( ))
298Arithmetic operators in bash
299Bitwise operators in arithmetic
300Ternary in arithmetic
301Base conversion in arithmetic
302let and (( )) commands
303Integer overflow in bash arithmetic
304Floating point with bc
305Floating point with awk
306Word splitting rules
307Filename expansion rules
308Process substitution <( )
309Process substitution >( )
310Process substitution versus pipes
311Using process substitution with diff
312Using process substitution with comm
313Using process substitution with while read
314Quoting for eval
315Why eval is dangerous
316printf %q for safe quoting
317Quoting in aliases
318Quoting in ssh remote commands
319Quoting in xargs and find -exec
320The * wildcard
321The ? wildcard
322Bracket expressions
323Character classes like [:alpha:]
324Negated brackets with [!...]
325Globs and hidden files
326dotglob option
327nullglob option
328failglob option
329nocaseglob option
330globstar and **
331extglob ?(pattern)
332extglob *(pattern)
333extglob +(pattern)
334extglob @(pattern)
335extglob !(pattern)
336GLOBIGNORE variable
337globskipdots option
338Glob sort order and locale
339Globs versus regular expressions
340When a glob matches nothing
341Globs in [[ ]] comparisons
342Globs in case patterns
343Globbing with very long lists
344ARG_MAX and glob limits
345Quoting globs to pass literally
346set -f to disable globbing
347Globbing and spaces in names
348Globbing in scripts safely
349File descriptors 0 1 and 2
350Redirecting stdout with >
351Appending with >>
352Redirecting stderr with 2>
353Merging with 2>&1
354The &> and &>> shortcuts
355Order of redirections matters
356Redirecting input with <
357Duplicating descriptors with n>&m
358Closing descriptors with n>&-
359Opening custom descriptors with exec
360Reading and writing with <>
361noclobber and >
362Here-documents basics
363Quoted here-document delimiters
364Indented here-documents with <<-
365Here-documents with variable expansion
366Here-documents feeding ssh
367Here-documents feeding cat to files
368Here-documents inside functions
369Here-strings with <<<
370Here-strings with read
371Redirecting a whole block
372Redirecting a whole script with exec
373Logging stdout and stderr to a file
374Swapping stdout and stderr
375tee for splitting output
376tee -a and process substitution
377/dev/null /dev/zero and /dev/full
378/dev/stdin /dev/stdout /dev/stderr
379/dev/tcp and /dev/udp pseudo-paths
380Named pipes with mkfifo
381Pipes and SIGPIPE
382Pipe buffering and stdbuf
383Pipelines and subshells
384lastpipe option
385pipefail option
386Capturing stderr into a variable
387Reading a file descriptor with read -u
388Temporary files with mktemp
389Cleaning temp files with traps
390if elif else chains
391Exit status as truth
392The test builtin
393[ ] versus [[ ]]
394String tests in [[ ]]
395Numeric tests -eq -lt and friends
396File tests -e -f -d -r -w -x
397File tests -s -L -nt -ot
398Regex matching with =~
399Capturing groups with BASH_REMATCH
400Storing regexes in variables
401Short-circuit AND and OR lists
402The conditional-list fallback trap
403Grouping with { } and ( )
404Subshell versus brace group
405Negation with !
406case with multiple patterns
407case fall-through with ;& and ;;&
408while loops
409until loops
410for in lists
411C-style for loops
412select menus
413break and continue with levels
414Infinite loops and exit conditions
415Reading files with while read -r
416Preserving whitespace with IFS= read
417Reading NUL-delimited input
418Loop over command output safely
419Loop over find results safely
420Looping over ranges
421Looping with seq
422Loop performance considerations
423Early exit patterns
424Retry loops with backoff
425Polling loops with timeouts
426Menu-driven scripts
427Looping over words in strings
428Looping over associative keys
429Looping over file lines in parallel
430Defining functions two ways
431Function arguments and positional params
432Function return codes
433Returning values by stdout
434Returning values with namerefs
435Local variables and recursion
436Recursion in bash
437Function overriding builtins with command
438command -v versus which
439type and type -a
440builtin command
441declare -f to print functions
442export -f for subshells
443Functions versus aliases
444Alias expansion rules
445unalias and alias scope
446source and the . builtin
447Sourcing with arguments
448Source guards and idempotence
449Library files for shell code
450Detecting sourced versus executed
451Namespacing function names
452Function tracing with declare -t
453Function tracing with trap RETURN
454Default arguments in functions
455Option parsing in functions
456Variadic functions
457Higher-order function patterns
458Callbacks in bash
459Memoization in bash
460Unit testing functions
461bats framework basics
462shellcheck usage
463shellcheck common warnings
464shfmt formatting
465Writing portable POSIX sh
466Bashisms to avoid
467dash versus bash
468Posix mode in bash
469Compatibility across bash versions
470trap basics
471Trapping EXIT
472Trapping ERR
473Trapping INT and TERM
474Trapping HUP for reload
475Trapping DEBUG
476Trapping RETURN
477Listing traps with trap -p
478Resetting traps
479Ignoring signals with trap ''
480Trap inheritance in subshells
481errtrace option
482Cleaning up temp files via EXIT
483Lockfiles with traps
484Graceful shutdown of loops
485Forwarding signals to child processes
486Waiting for children with wait
487wait -n for first finisher
488wait with PIDs and status
489Signal handling while in wait
490Traps and sleep interruptions
491Traps in functions
492Exit codes from signals 128+N
493Error handling strategies
494set -e behavior details
495set -e pitfalls in conditionals
496set -u and unset arrays
497set -o pipefail interactions
498inherit_errexit option
499Writing die and warn helpers
500Stack traces on error
501Retrying commands
502Timeouts with timeout command
503Idempotent scripts
504Jobs table and %N specs
505Backgrounding with &
506Suspending with Ctrl-Z
507fg and bg
508jobs -l and -p
509disown -h and -a
510Job control in scripts
511set -m monitor mode
512Process groups and sessions
513Controlling terminal
514wait for background jobs
515Parallelism with xargs -P
516Parallelism with background loops
517Limiting concurrency in bash
518GNU parallel basics
519parallel with ::: and :::+
520parallel --pipe
521parallel --jobs and --load
522parallel --joblog and --resume
523Semaphores with mkfifo
524Semaphores with flock
525The coproc keyword
526Named coprocs
527Talking to a coproc
528Closing coproc descriptors
529Coprocs versus named pipes
530Co-processes for bc
531Subshells and ( )
532Background subshells
533Command groups in pipelines
534Process substitution and wait
535Detaching with setsid
536Detaching with nohup
537Running under screen
538Running under tmux
539tmux sessions windows and panes
540tmux copy mode and scripting
541tmux config and plugins
542screen basics and detach
543Surviving logout reliably
544Readline basics
545Emacs mode key bindings
546Vi mode in readline
547.inputrc configuration
548bind command
549Custom key bindings
550Reverse search with Ctrl-R
551History expansion with !!
552History designators !$ !^ !*
553History modifiers :h :t :r :e
554Quick substitution ^old^new
555fc command
556history -a -n -r
557Shared history across terminals
558Programmable completion basics
559complete -F functions
560complete -W word lists
561compgen
562bash-completion package
563Writing a completion script
564Completion for subcommands
565Prompt customization PS1
566Prompt escape sequences
567Colors in prompts with tput
568Git branch in prompt
569Multi-line prompts
570Startup files overview
571.bashrc versus .bash_profile
572.profile and login shells
573/etc/profile and /etc/profile.d
574.bash_logout
575Interactive versus non-interactive shells
576Login versus non-login shells
577shopt options list
578checkwinsize and autocd
579cdspell and dirspell
580histappend and cmdhist
581pushd popd dirs
582Directory stack tricks
583Aliases for productivity
584Functions for productivity
585zsh differences overview
586fish differences overview
587Choosing a shell
588Dotfile management with git
589Dotfile management with stow
590Script skeleton template
591Usage and help text
592getopts basics
593getopts with optional arguments
594Long options with getopt
595Long options by case loops
596Parsing subcommands
597Validating arguments
598Argument defaults via expansion
599Reading config files
600Parsing key=value files safely
601Parsing INI files
602Parsing JSON with jq
603jq filters and pipes
604jq select map and reduce
605jq raw output and arguments
606Parsing YAML with yq
607Parsing CSV in bash
608Parsing XML with xmllint
609Parsing HTML basics
610Colored output with ANSI codes
611Detecting terminals with -t
612Progress bars in bash
613Spinners in bash
614Logging functions
615Log levels and timestamps
616Date arithmetic in bash
617Date formatting with date
618Parsing dates with date -d
619Random strings and passwords
620UUIDs from the shell
621Hashing in scripts
622Base64 in scripts
623URL encoding in bash
624Lockfiles and single instance
625PID files
626Daemonizing a script
627Running as root checks
628Self-updating scripts
629Script directory resolution
630Symlink resolution with readlink -f
631Safe temporary directories
632Atomic file writes
633Atomic directory swaps
634Checking dependencies
635Portable shebangs with env
636Exit code conventions
637Man page for your script
638Packaging scripts as deb
639Embedding binaries in scripts with makeself
640Performance profiling of scripts
641Avoiding subshell forks
642Avoiding useless cat
643Bash versus Python decision

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Lesson 397 of 3,142·9. Bash in DepthFree lesson

File tests -s -L -nt -ot

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