roalcantara/0_tldr.zsh

## 0_tldr.zsh
## TL;DR

setopt extendedglob
ls *(<tab>                                                    # to get help regarding globbing
rm ../debianpackage(.)                                        # remove files only
ls -d *(/)                                                    # list directories only
ls /etc/*(@)                                                  # list symlinks only
ls -l *.(png|jpg|gif)                                         # list pictures only
ls *(*)                                                       # list executables only
ls /etc/**/zsh                                                # which directories contain 'zsh'?
ls **/*(-@)                                                   # list dangling symlinks ('**' recurses down directory trees)
ls foo*~*bar*                                                 # match everything that starts with foo but doesn't contain bar
ls *(e:'file $REPLY | grep -q JPEG':)                         # match all files of which file says that they are JPEGs
ls -ldrt -- *(mm+15)                                          # List all files older than 15mins
ls -ldrt -- *(.mm+15)                                         # List Just regular files
ls -ld /my/path/**/*(D@-^@)                                   # List the unbroken sysmlinks under a directory.
ls -Lldrt -- *(-mm+15)                                        # List the age of the pointed to file for symlinks
ls -l **/README                                               # Search for `README' in all Subdirectories
ls -l foo<23->                                                # List files beginning at `foo23' upwards (foo23, foo24, foo25, ..)
ls -l 200406{04..10}*(N)                                      # List all files that begin with the date strings from June 4 through June 9 of 2004
ls -l 200306<4-10>.*                                          # or if they are of the form 200406XX (require ``setopt extended_glob'')
ls -l *.(c|h)                                                 # Show only all *.c and *.h - Files
ls -l *(R)                                                    # Show only world-readable files
ls -fld *(OL)                                                 # Sort the output from `ls -l' by file size
ls -fl *(DOL[1,5])                                            # Print only 5 lines by "ls" command (like ``ls -laS | head -n 5'')
ls -l *(G[users])                                             # Show only files are owned from group `users'
ls *(L0f.go-w.)                                               # Show only empty files which nor `group' or `world writable'
ls *.c~foo.c                                                  # Show only all *.c - files and ignore `foo.c'
print -rl /home/me/**/*(D/e{'reply=($REPLY/*(N[-1]:t))'})     # Find all directories, list their contents and output the first item in the above list
print -rl /**/*~^*/path(|/*)                                  # Find command to search for directory name instead of basename
print -l ~/*(ND.^w)                                           # List files in the current directory are not writable by the owner
print -rl -- *(Dmh+10^/)                                      # List all files which have not been updated since last 10 hours
print -rl -- **/*(Dom[1,10])                                  # List the ten newest files in directories and subdirs (recursive)
print -rl -- /path/to/dir/**/*(D.om[5,10])                    # Display the 5-10 last modified files
print -rl -- **/*.c(D.OL[1,10]:h) | sort -u                   # Print the path of the directories holding the ten biggest C regular files in the current directory and subdirectories.
setopt dotglob ; print directory/**/*(om[1])                  # Find most recent file in a directory
for a in ./**/*\ *(Dod); do mv $a ${a:h}/${a:t:gs/ /_}; done  # Remove spaces from filenames

# * (#s) or (#e) for what ^ and $ are in regexps (beginning of line/end of line)
# * (#b) or (#m) to enable backreferences
# * (#i) to match case insensitive
# * (#a) to match approximately (certain errors are ignored, e.g. “(#a1)foo*” matches the string “ofobar”)

# sources:
#   * https://github.com/mika/zsh-pony#globbing--glob-qualifiers
#   * https://strcat.de/zsh/#tipps

## 0a_intro.zsh
## Globbing

# A glob is a short expression that lets you filter files by their name
# 99% of the time, there’s an asterisk involved.

## Given the following structure
#
# zsh_demo
# ├── data
# │   ├── africa
# │   │   ├── kenya
# │   │   │   ├── literacy.txt
# │   │   │   ├── income.txt
# │   │   │   └── population.txt
# │   │   └── ...
# │   ├── asia
# │   │   ├── ...
# │   └── europe
# │       ├── ...
# └── data
#     ├── africa
#     │   ├── kenya
#     │   │   ├── literacy_index.txt
#     │   │   ├── median_income.txt
#     │   │   └── population_by_province.txt
#     │   └── ...
#     ├── ...

ls zsh_demo/**/*.txt # <= this is a glob

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/

## 1a_File_picking.zsh
### 1. File picking

# Globs get replaced by the names of the files that match the glob expression.

ls zsh_demo                                 # list every file directly below the zsh_demo folder
ls zsh_demo/*                               # list every file in the folders directly below the zsh_demo folder
ls zsh_demo/*/*                             # list every file in every folder two levels below the zsh_demo folder
ls zsh_demo/**/*                            # list every file anywhere below the zsh_demo folder
ls zsh_demo/**/*.txt                        # list every file that ends in .txt in every folder at any level below the zsh_demo folder
print -l zsh_demo/data/*/*                  # list folders separated by new lines
echo zsh_demo/data/*/*                      # list folders separated by spaces
for country_folder in zsh_demo/data/*/*; do # for each folder
  # do something
done

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/

## 1b_glob_operators.zsh
## 1.1 Glob Operators

# Filter by file names

ls -l zsh_demo/**/*<1-10>.txt                # list text files that end in a number from 1 to 10
ls -l zsh_demo/**/[a]*.txt                   # list text files that start with the letter a
ls -l zsh_demo/**/(ab|bc)*.txt               # list text files that start with either ab or bc
ls -l zsh_demo/**/[^cC]*.txt                 # list text files that don't start with a lower or uppercase c

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/
# more: http://zsh.sourceforge.net/Doc/Release/Expansion.html#Filename-Generation

## 1c_glob_qualifiers.zsh
## 2.1 Glob Qualifiers

# Filter by file type, size, modification date
# Glob qualifiers are surrounded in parentheses (), and appear at the end of a glob to make it more stringent.

print -l zsh_demo/**/*(/)                # show only directories
print -l zsh_demo/**/*(.)                # show only regular files
ls -l zsh_demo/**/*(L0)                  # show empty files
ls -l zsh_demo/**/*(Lk+3)                # show files greater than 3 KB
print -l zsh_demo/**/*(mh-1)             # show files modified in the last hour
ls -l zsh_demo/**/*(om[1,3])             # sort files from most to least recently modified and show the last 3

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/

## 1d_glob_qualifiers_filter.zsh
## 2.1 Glob Qualifiers

# To FIND every continent that DOES NOT CONTAIN a country named malta
#
print -l zsh_demo/*/*(e:'[[ ! -e $REPLY/malta ]]':)

# 1. After the e, the string has to be delimited by a convenient character (in this case, a colon :),
#    and the code must be surrounded by single quotes ',
#    so the actual command is just [[ ! -e $REPLY/malta ]].
#
# 2. The $REPLY variable contains every file name of the ones specified by the glob zsh_demo/*/* in turn,
#    but only a single file at a time.
#
# 3. [[ -e file ]] is a conditional expression that returns true if the file exists.
#    We want it to return true when the file called malta doesn’t exist, so we reverse it with !.
#
# 4. When the code is executed, the $REPLY variable takes the value of the next file and the code is executed again.

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/

## 1e_glob_qualifiers_sort.zsh
## 2.1 Glob Qualifiers

# To SORT files from most to least recently modified and show the last 3
#
ls -l zsh_demo/**/*(om[1,3])

# Five different things are going on at the same time:

# 1. The . tells the glob to only show regular files (no directories, symbolic links, or other types of files).
#
# 2. The Lm-2 tells the glob to show files smaller than 2 MB.
#   * Use - for smaller, and + for greater; don’t use anything if you want to specify the exact size (Lm2).
#   * Use m for megabytes, k for kilobytes, or nothing for just bytes (notice that these letters must appear before the sign).
#
# 3. The mh-1 tells the glob to show files modified in the last hour
#   * Use - if you want files modified within the last X units of time, and + for files modified more than X units of time ago.
#   * Use M for Months, w for weeks, h for hours, m for minutes, and s for seconds (notice that these leters must appear before the sign).
#
# 4. The om tells the glob to sort the remaining files by their modification date.
#   * A lowercase o sorts by most recent first, to use the reverse order, make it uppercase O.
#   * Use m to sort by modification date, and L to sort by size (oL).
#
# 5. The [1,3] tells the glob to show the first 3 files (since we just sorted the files, these will be the most recently modified ones).
#   * You can also show a single file (for example, the second one [2])

# more: http://zsh.sourceforge.net/Doc/Release/Expansion.html#Filename-Generation
# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/

## 1f_glob_delete.zsh
### DELETE examples

## delete only the oldest file in a directory
rm ./*filename*(Om[1])

## Find and delete the files which are older than a given parameter (seconds/minutes/hours)
#
rm -f /Dir/**/*(.mh+3)             # deletes all regular file in /Dir that are older than 3 hours
rm -f /Dir/**/*(@mm+3)             # deletes all symlinks in /Dir that are older than 3 minutes
rm -f /Dir/**/*(ms+30^/)           # deletes all non dirs in /Dir that are older than 30 seconds
rm ./**/*(.Dmh+1,.DL0)             # deletes all folders, sub-folders and files older than one hour
rm -f **/*(mh+6)                   # deletes all files more than 6 hours old
rm ./*(Om[1,-11])                  # removes all files but the ten newer ones (delete all but last 10 files in a directory)

## remove empty directories afterwards
rmdir ./**/*(/od) 2> /dev/null

## Note: If you get a arg list too long, you use the builtin rm. For example:
zmodload zsh/files ; rm -f **/*(mh+6)
#  or use the zargs function:
autoload zargs ; zargs **/*(mh+6) -- rm -f

# source: https://strcat.de/zsh/#tipps

## 1j_glob_chmod.zsh
### CHMOD examples

## Recursive chmod
chmod 700 **/(.)                    # Only files
chmod 700 **/(/)                    # Only directories
chown 666 **/*(u102)                # Change the UID from 102 to 666

## find all files without a valid owner
chmod someuser /**/*(D^u:${(j.:u:.)${(f)"$(</etc/passwd)"}%%:*}:)

## Search all files in /home/*/*-mail/ with a setting ``chmod -s'' flag
# (recursive, include dotfiles) remove the setgid/setuid flag and print a message
chmod -s /home/*/*-mail(DNs,S) /home/*/*-mail/**/*(DNs,S))

# source: https://strcat.de/zsh/#tipps

## 1k_glob_find.zsh
### FIND examples

## find directories that contain both "index.php" and "index.html", or in general, directories
# that contain more than one file matching "index.*"
ls **/*(D/e:'[[ -e $REPLY/index.php && -e $REPLY/index.html ]]':)

## Find files with size == 0 and send a mail
files=(**/*(ND.L0m+0m-2)) > (( $#files > 0 )) && print -rl -- $files | mailx -s "empty files" foo@bar.tdl

## Print out all of the files in that directory in 2 columns
print -rC2 -- ${1:[...]}/*(D:t)
#            ^- number ob columns
# or - if you feel concerned about special characters - use
list=(${1:[...]}/*(ND:t))
(($#list)) && print -rC2 -- ${(V)list}

## Show data to *really* binary format
zsh -ec 'while {} {printf %.8x $n;repeat 8 \
  > {read -ku0 a printf \ %.8d $(([##2]#a))};print;((n+=8))}' < binary

## A User's Guide to the Z-Shell /5.9: Filename Generation and Pattern Matching
# find all files in all subdirectories, searching recursively, which have a given
# name, case insensitive, are at least 50 KB large, no more than a week old and
# owned by the root user, and allowing up to a single error in the spelling of
# the name. In fact, the required expression looks like this:
ls **/(#ia1)name(LK+50mw-1u0)

## find all the empty directories in a tree
for f in ***/*(/l2); do foo=($f/*(N)); [[ -z $foo ]] && print $f; done
# Note:Since Zsh 4.2.1(?) the glob qualifier F indicates a non-empty directory.
  Hence *(F) indicates all subdirectories with entries, *(/^F) means all subdirectories with no
  entries.
ls -ld *(/^F)

## Use find(1) to find all directories except the ".svn" ones,
# then use grep on all *.c/*.h/*.S files in each directory.
setopt extendedglob
grep pattern (^.svn/)#*.[xhS](.)  # skips dot files and dot directories
# or - without Zsh
find . -type d ! -name .svn | sed 's/./\\&/g;s|.*|grep whatever &/*.[xhS]|' | sh

## Quote from Usenet
# > I need to write a script that searches through a folder on my Linux
# > home server and copies only files where the width is greater than the
# > height, but it also needs to flatten the directory structure and
# > rename files as it copies.  So the first picture found may be several
# > directories deep in the source but this should be copied to the root
# > of the SD card and named say 00000001.JPG and the next file found
# > where width > height should be copied and renamed 00000002.JPG.
width_greater_than_height() {
  local w h
  identify -format '%w %h' ${1-$REPLY} |
    read w h && ((w > h))
}
typeset -Z8 i=0
setopt extendedglob
for f (**/*.(#i)jp(e|)g(D.+width_greater_than_height)) {
  ((i++))
  cp -- $f /path/to/dest/$i.JPG
}

# source: https://strcat.de/zsh/#tipps

## 2a_variable_transformations.zsh
### 2. Variable transformations: Modifiers

# Inside the parentheses, each modifiers is preceded by a colon :, which makes them easily distinguishable from qualifiers.

print -l zsh_demo/data/europe/poland/*.txt          # A plain old glob
print -l zsh_demo/data/europe/poland/*.txt(:t)      # Return the file name (t stands for tail)
print -l zsh_demo/data/europe/poland/*.txt(:t:r)    # Return the file name without the extension (r stands for remove_extension, I think)
print -l zsh_demo/data/europe/poland/*.txt(:e)      # Return the extension
print -l zsh_demo/data/europe/poland/*.txt(:h)      # Return the parent folder of the file (h stands for head)
print -l zsh_demo/data/europe/poland/*.txt(:h:h)    # Return the parent folder of the parent
print -l zsh_demo/data/europe/poland/*.txt([1]:h)   # Return the parent folder of the first file
                                                    # Remember you can combine qualifiers and modifiers.

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/

## 2b_parameter_expansion.zsh
### 2. Variable transformations: Parameter expansion

# Modifiers are not only for globs, you can also use them with variables (the technical term is parameter expansion):

# If you want to store a glob in a variable, you must use parentheses
my_file=(zsh_demo/data/europe/poland/*.txt([1]))

print -l $my_file
print -l $my_file(:h)       # this is the syntax we saw before
print -l ${my_file:h}       # I find this syntax more convenient
print -l ${my_file(:h)}     # DO NOT mix the two, or you'll get an ERROR!
print -l ${my_file:u}       # the :u modifier makes the text uppercase

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/

## 2c_modifiers_e.zsh
### 2. Variable transformations: Modifiers
#
## :e(xtension)

foo=23.42                    # Remove all but the extension
echo $foo:e
# -> 42

# source: https://strcat.de/zsh/#tipps

## 2c_modifiers_gs.zsh
### 2. Variable transformations: Modifiers
#
# The `:gs` modifier (g stands for global)
# Used to more than one substitution

my_variable="aaa"

echo ${my_variable:s/a/A/}
# -> Aaa

echo ${my_variable:gs/a/A/}
# -> AAA

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/

## 2c_modifiers_h.zsh
### 2. Variable transformations: Modifiers
#
# (:h)ead - like `dirname'.

echo =ls(:h)                 # Remove a trailing pathname component, leaving the head.
# -> /bin

echo =ls(:h)                 # Print the new command but do not execute it. Only works with history expansion.
# -> /bin

!echo:p
echo =ls(:h)

for f (*.sh) mv $f $f:h      # Remove the suffix from each file (*.sh in this example)

# source: https://strcat.de/zsh/#tipps

## 2c_modifiers_l.zsh
### 2. Variable transformations: Modifiers
#
# (:l)owercase

bar=FOOBAR
echo $bar:l               # Convert the words to all lowercase.
# -> foobar

# source: https://strcat.de/zsh/#tipps

## 2c_modifiers_misc.zsh
### 2. Variable transformations: Modifiers


foo="one two three four"
print -r -- "${(C)var}"          # convert 1st char of a word to uppercase
# -> One Two Three Four

a=( a a f 1 3 b b 3 5 4 4 )      # Eliminate the duplicated elements of an array
a=("${(u@)a")                    # and keep the remain emements order appeared in the original

# source: https://strcat.de/zsh/#tipps

## 2c_modifiers_q.zsh
### 2. Variable transformations: Modifiers
#
# (:q)uote


bar="23'42"
echo $bar:q                       # Quote the substituted words, escaping further substitutions.
# -> 23\'42

# source: https://strcat.de/zsh/#tipps

## 2c_modifiers_r.zsh
### 2. Variable transformations: Modifiers
#
# :r(rest)

for f (*.sh) mv $f $f:r               # Remove the suffix from each file (*.sh in this example)

# source: https://strcat.de/zsh/#tipps

## 2c_modifiers_s.zsh
### 2. Variable transformations: Modifiers
#
# The `:s` modifier
#
# Let’s say we wanted to calculate the maximum income for each country,
# and store it in a file named {country}_max_income.txt in the corresponding calculations folder.
#
# We can do this easily using the modifier (:s):

# Each time the for loop runs, the $file variable is set to a different income file:
for file in zsh_demo/data/**/income.txt ; do
  # We use the :h modifier to get rid of the file name (zsh_demo/data/africa/kenya/),
  # and then we use the :s modifier to substitute data with calculations: (zsh_demo/calculations/africa/kenya/)
  output_dir=${file:h:s/data/calculations/}

  # We use the :t modifier to get the name of the country (kenya)
  country=${output_dir:t}

  # Then we stick a slash / between the $output_dir and $country variables,
  # and append _max_income.txt to get our output file path
  #   (ex: zsh_demo/calculations/africa/kenya/kenya_max_income.txt)
  output_file="${output_dir}/${country}_max_income.txt"

  # The $RANDOM variable gives you a random number every time you call it
  # (just a quick way of generating some content).
  # The right arrow > saves the calculation to the output file.
  echo "The max salary is $RANDOM dollars" > $output_file
done

# The `grep "" bunch_of_files` command is a quick-and-dirty way to show the name of each file and its contents
# we could have also used `head bunch_of_files`
grep "" zsh_demo/calculations/**/*_max_income.txt

#
# You can use any character to separate the :s and the strings:
#

my_variable="path/abcd"
echo ${my_variable:s/bc/BC/} # path/aBCd
echo ${my_variable:s_bc_BC_} # path/aBCd

## escaping the slash \/
echo ${my_variable:s/\//./}
# -> path.abcd

## to substitute the slash (/) without escape
echo ${my_variable:s_/_._}
# -> # path.abcd

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/

## 2c_modifiers_t.zsh
### 2. Variable transformations: Modifiers
#
# :t(tail) - like `basename'.

foo=/usr/src/linux
echo $foo:t                   # Remove a filename extension of the form `.xxx', leaving the root name.
# -> linux
echo =ls(:t)                  # Remove all leading pathname components, leaving the tail.
# -> ls
for f (*.sh) mv $f $f:t       # Remove the suffix from each file (*.sh in this example)

# source: https://strcat.de/zsh/#tipps

## 2c_modifiers_u.zsh
### 2. Variable transformations: Modifiers
#
# :u(ppercase)

bar=foobar
echo $bar:u                 # Convert the words to all uppercase.
# -> FOOBAR

# source: https://strcat.de/zsh/#tipps

## 2e_expansion_flag_s.zsh
### 2. Variable transformations: Expansion flags
#
# The s(plit) flag
# Let's say somebody gave you these updated files
# and told you to replace the old ones

echo $RANDOM > zsh_demo/africa_malawi_population_2014.txt
echo $RANDOM > zsh_demo/asia_nepal_income_2014.txt
echo $RANDOM > zsh_demo/europe_malta_literacy_2014.txt

# How would you move them to their appropriate folders?

# for each $file (ex: zsh_demo/europe_malta_literacy_2014.txt)
for file in zsh_demo/*.txt; do
  # 1. Use the :t modifier to get rid of everything to the left of the first slash /.
  #    $ echo ${file:t}
  #    $ -> europe_malta_literacy_2014.txt
  #
  # 2. Use the (s) expansion flag to split the file name at each underscore _.
  #    $ echo ${(s._.)file:t}
  #    $ -> europe malta literacy 2014.txt
  #
  # 3. Without parentheses, file_info contains the wrong information:
  #   # file_info=${(s._.)file:t}
  #   $ echo $file_info
  #   $ -> europe_malta_literacy_2014.txt
  #
  file_info=(${(s._.)file:t}) # So, surround everything with parentheses
  #    $ echo $file_info
  #    $ -> europe malta literacy 2014.txt

  # 5. Use an auxiliary variable for continent, country, and data.
  #    Since $file_info is now an array, we can refer to its elements by using a numeric index.
  #    $ echo ${file_info[3]}
  #    $ -> literacy
  continent=$file_info[1]
  country=$file_info[2]
  data=$file_info[3]

  # 6. Use the auxiliary variables to specify the path where we want to move the new files
  mv -f $file zsh_demo/data/${continent}/${country}/${data}.txt
done

# Check the contents of the files (.) modified (m) in the last
# 5 minutes (m-5) to see what you just did
grep "" zsh_demo/**/*(.mm-5)

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/
# more: http://zsh.sourceforge.net/Doc/Release/Expansion.html#Parameter-Expansion

## 2f_expansion_flag_j.zsh
### 2. Variable transformations: Expansion flags
#
# The j(oin) flag:
# Which does the opposite of the split flag

my_array=(a b c d)
echo ${(j.-.)my_array}
# -> a-b-c-d

# Since we are joining using dots (.), it makes more sense to
# use underscores (_) to separate the dots and the j
echo ${(j_._)my_array}
# -> a.b.c.d

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/

## 3a_event_designators.zsh
### 3. Magic tabbing: Event designators
#
# An event designator references one of the commands that we have previously entered.
# They always start with a bang !:

# show the previous command
echo a b c
!! # instead of pressing <Enter>, press <Tab>, then press <Enter>

# show two commands ago
echo d e f
echo g h i
!-2 # press <Tab>, then press <Enter>

# Note: If you press <Enter> instead of <Tab>,
#       the event designator will also get replaced,
#       but you’ll still have to press <Enter> one more time to run it.

# They really come in handy is to add previous arguments to our current command.

# add the last argument
ls zsh_demo/data/asia/laos/population.txt
ls -l !!1 # press <Tab>, then press <Enter>

# add all the previous arguments
echo a b c
print -l !!* # press <Tab>, then press <Enter>

# So, we reference previous arguments in two steps:

# 1. Specify which command you are interested in
#   * The previous command !! is the one you’ll use most often.
#   * If you want to go back farther, use the minus sign - and a number: !-2, !-3.
#   * You can also use the current command !#

# 2. Pick what arguments you want to reuse
#   * To pick an argument from the previous command,
#     just add a number !!1, !!2. Use !!$ for the last argument.
#   * To pick an argument from two or more commands ago,
#     add a colon : before the number !-2:1 (because!-21 means something else).
#   * If you want to reference all the arguments, use an asterisk * !!* !-2:*.
#   * If you want skip all the arguments except the first one or two,
#     add a number before the asterisk !!2*, !-2:2*.

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/

## 3b_event_designators_2.zsh
### 3. Magic tabbing: Event designators
#
# Some useful examples

mv zsh_demo/data/asia/laos/population.txt !#1
# press <Tab>
# now you can easily change the second argument
# (use Control W to delete every up to the first slash)

ls zsh_demo/data/europe/malta/literacy.txt
awk '$1 > 3' !$
# press <Tab>
# !$ is a shortcut for !!$

ls zsh_demo/*/*/nepal/literacy.txt
ls zsh_demo/*/*/malta/literacy.txt
ls -l !-2:1
# press <Tab>
# now you can see the details of the nepal file

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/
# more: http://zsh.sourceforge.net/Doc/Release/Expansion.html#History-Expansion

## 3c_event_designators_3.zsh
### 3. Magic tabbing: Event designators
#
# Pressing <Tab> lets you expand not only old commands, but globs,
# variables (when they use the ${} syntax), and even lazily-typed paths!

ls zsh_demo/*/*/nepal/literacy.txt
# press <Tab>

my_var="1 2 3"
echo ${my_var}
# press <Tab>

ls z/d/a/l
# press <Tab>
# 🤯

# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/
# more: http://zsh.sourceforge.net/Doc/Release/Expansion.html#History-Expansion
	## TL;DR

	setopt extendedglob
	ls *(<tab> # to get help regarding globbing
	rm ../debianpackage(.) # remove files only
	ls -d *(/) # list directories only
	ls /etc/*(@) # list symlinks only
	ls -l *.(png\|jpg\|gif) # list pictures only
	ls () # list executables only
	ls /etc/**/zsh # which directories contain 'zsh'?
	ls */(-@) # list dangling symlinks ('**' recurses down directory trees)
	ls foo~bar* # match everything that starts with foo but doesn't contain bar
	ls *(e:'file $REPLY \| grep -q JPEG':) # match all files of which file says that they are JPEGs
	ls -ldrt -- *(mm+15) # List all files older than 15mins
	ls -ldrt -- *(.mm+15) # List Just regular files
	ls -ld /my/path/*/(D@-^@) # List the unbroken sysmlinks under a directory.
	ls -Lldrt -- *(-mm+15) # List the age of the pointed to file for symlinks
	ls -l **/README # Search for `README' in all Subdirectories
	ls -l foo<23-> # List files beginning at `foo23' upwards (foo23, foo24, foo25, ..)
	ls -l 200406{04..10}*(N) # List all files that begin with the date strings from June 4 through June 9 of 2004
	ls -l 200306<4-10>.* # or if they are of the form 200406XX (require ``setopt extended_glob'')
	ls -l .(c\|h) # Show only all .c and *.h - Files
	ls -l *(R) # Show only world-readable files
	ls -fld *(OL) # Sort the output from `ls -l' by file size
	ls -fl *(DOL[1,5]) # Print only 5 lines by "ls" command (like ``ls -laS \| head -n 5'')
	ls -l *(G[users]) # Show only files are owned from group `users'
	ls *(L0f.go-w.) # Show only empty files which nor `group' or `world writable'
	ls .c~foo.c # Show only all .c - files and ignore `foo.c'
	print -rl /home/me/*/(D/e{'reply=($REPLY/*(N[-1]:t))'}) # Find all directories, list their contents and output the first item in the above list
	print -rl /*/~^/path(\|/) # Find command to search for directory name instead of basename
	print -l ~/*(ND.^w) # List files in the current directory are not writable by the owner
	print -rl -- *(Dmh+10^/) # List all files which have not been updated since last 10 hours
	print -rl -- */(Dom[1,10]) # List the ten newest files in directories and subdirs (recursive)
	print -rl -- /path/to/dir/*/(D.om[5,10]) # Display the 5-10 last modified files
	print -rl -- */.c(D.OL[1,10]:h) \| sort -u # Print the path of the directories holding the ten biggest C regular files in the current directory and subdirectories.
	setopt dotglob ; print directory/*/(om[1]) # Find most recent file in a directory
	for a in ./*/\ *(Dod); do mv $a ${a:h}/${a:t:gs/ /_}; done # Remove spaces from filenames

	# * (#s) or (#e) for what ^ and $ are in regexps (beginning of line/end of line)
	# * (#b) or (#m) to enable backreferences
	# * (#i) to match case insensitive
	# * (#a) to match approximately (certain errors are ignored, e.g. “(#a1)foo*” matches the string “ofobar”)

	# sources:
	# * https://github.com/mika/zsh-pony#globbing--glob-qualifiers
	# * https://strcat.de/zsh/#tipps
	## Globbing

	# A glob is a short expression that lets you filter files by their name
	# 99% of the time, there’s an asterisk involved.

	## Given the following structure
	#
	# zsh_demo
	# ├── data
	# │ ├── africa
	# │ │ ├── kenya
	# │ │ │ ├── literacy.txt
	# │ │ │ ├── income.txt
	# │ │ │ └── population.txt
	# │ │ └── ...
	# │ ├── asia
	# │ │ ├── ...
	# │ └── europe
	# │ ├── ...
	# └── data
	# ├── africa
	# │ ├── kenya
	# │ │ ├── literacy_index.txt
	# │ │ ├── median_income.txt
	# │ │ └── population_by_province.txt
	# │ └── ...
	# ├── ...

	ls zsh_demo/*/.txt # <= this is a glob

	# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/
	### 1. File picking

	# Globs get replaced by the names of the files that match the glob expression.

	ls zsh_demo # list every file directly below the zsh_demo folder
	ls zsh_demo/* # list every file in the folders directly below the zsh_demo folder
	ls zsh_demo// # list every file in every folder two levels below the zsh_demo folder
	ls zsh_demo/*/ # list every file anywhere below the zsh_demo folder
	ls zsh_demo/*/.txt # list every file that ends in .txt in every folder at any level below the zsh_demo folder
	print -l zsh_demo/data// # list folders separated by new lines
	echo zsh_demo/data// # list folders separated by spaces
	for country_folder in zsh_demo/data//; do # for each folder
	# do something
	done

	# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/
	## 1.1 Glob Operators

	# Filter by file names

	ls -l zsh_demo/*/<1-10>.txt # list text files that end in a number from 1 to 10
	ls -l zsh_demo/*/[a].txt # list text files that start with the letter a
	ls -l zsh_demo/*/(ab\|bc).txt # list text files that start with either ab or bc
	ls -l zsh_demo/*/[^cC].txt # list text files that don't start with a lower or uppercase c

	# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/
	# more: http://zsh.sourceforge.net/Doc/Release/Expansion.html#Filename-Generation
	## 2.1 Glob Qualifiers

	# Filter by file type, size, modification date
	# Glob qualifiers are surrounded in parentheses (), and appear at the end of a glob to make it more stringent.

	print -l zsh_demo/*/(/) # show only directories
	print -l zsh_demo/*/(.) # show only regular files
	ls -l zsh_demo/*/(L0) # show empty files
	ls -l zsh_demo/*/(Lk+3) # show files greater than 3 KB
	print -l zsh_demo/*/(mh-1) # show files modified in the last hour
	ls -l zsh_demo/*/(om[1,3]) # sort files from most to least recently modified and show the last 3

	# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/
	## 2.1 Glob Qualifiers

	# To FIND every continent that DOES NOT CONTAIN a country named malta
	#
	print -l zsh_demo//(e:'[[ ! -e $REPLY/malta ]]':)

	# 1. After the e, the string has to be delimited by a convenient character (in this case, a colon :),
	# and the code must be surrounded by single quotes ',
	# so the actual command is just [[ ! -e $REPLY/malta ]].
	#
	# 2. The $REPLY variable contains every file name of the ones specified by the glob zsh_demo// in turn,
	# but only a single file at a time.
	#
	# 3. [[ -e file ]] is a conditional expression that returns true if the file exists.
	# We want it to return true when the file called malta doesn’t exist, so we reverse it with !.
	#
	# 4. When the code is executed, the $REPLY variable takes the value of the next file and the code is executed again.

	# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/
	## 2.1 Glob Qualifiers

	# To SORT files from most to least recently modified and show the last 3
	#
	ls -l zsh_demo/*/(om[1,3])

	# Five different things are going on at the same time:

	# 1. The . tells the glob to only show regular files (no directories, symbolic links, or other types of files).
	#
	# 2. The Lm-2 tells the glob to show files smaller than 2 MB.
	# * Use - for smaller, and + for greater; don’t use anything if you want to specify the exact size (Lm2).
	# * Use m for megabytes, k for kilobytes, or nothing for just bytes (notice that these letters must appear before the sign).
	#
	# 3. The mh-1 tells the glob to show files modified in the last hour
	# * Use - if you want files modified within the last X units of time, and + for files modified more than X units of time ago.
	# * Use M for Months, w for weeks, h for hours, m for minutes, and s for seconds (notice that these leters must appear before the sign).
	#
	# 4. The om tells the glob to sort the remaining files by their modification date.
	# * A lowercase o sorts by most recent first, to use the reverse order, make it uppercase O.
	# * Use m to sort by modification date, and L to sort by size (oL).
	#
	# 5. The [1,3] tells the glob to show the first 3 files (since we just sorted the files, these will be the most recently modified ones).
	# * You can also show a single file (for example, the second one [2])

	# more: http://zsh.sourceforge.net/Doc/Release/Expansion.html#Filename-Generation
	# source: http://reasoniamhere.com/2014/01/11/outrageously-useful-tips-to-master-your-z-shell/
	### DELETE examples

	## delete only the oldest file in a directory
	rm ./filename(Om[1])

	## Find and delete the files which are older than a given parameter (seconds/minutes/hours)
	#
	rm -f /Dir/*/(.mh+3) # deletes all regular file in /Dir that are older than 3 hours
	rm -f /Dir/*/(@mm+3) # deletes all symlinks in /Dir that are older than 3 minutes
	rm -f /Dir/*/(ms+30^/) # deletes all non dirs in /Dir that are older than 30 seconds
	rm ./*/(.Dmh+1,.DL0) # deletes all folders, sub-folders and files older than one hour
	rm -f */(mh+6) # deletes all files more than 6 hours old
	rm ./*(Om[1,-11]) # removes all files but the ten newer ones (delete all but last 10 files in a directory)

	## remove empty directories afterwards
	rmdir ./*/(/od) 2> /dev/null

	## Note: If you get a arg list too long, you use the builtin rm. For example:
	zmodload zsh/files ; rm -f */(mh+6)
	# or use the zargs function:
	autoload zargs ; zargs */(mh+6) -- rm -f

	# source: https://strcat.de/zsh/#tipps
	### CHMOD examples

	## Recursive chmod
	chmod 700 **/(.) # Only files
	chmod 700 **/(/) # Only directories
	chown 666 */(u102) # Change the UID from 102 to 666

	## find all files without a valid owner
	chmod someuser /*/(D^u:${(j.:u:.)${(f)"$(</etc/passwd)"}%%:*}:)

	## Search all files in /home//-mail/ with a setting ``chmod -s'' flag
	# (recursive, include dotfiles) remove the setgid/setuid flag and print a message
	chmod -s /home//-mail(DNs,S) /home//-mail/*/(DNs,S))

	# source: https://strcat.de/zsh/#tipps
	### FIND examples

	## find directories that contain both "index.php" and "index.html", or in general, directories
	# that contain more than one file matching "index.*"
	ls */(D/e:'[[ -e $REPLY/index.php && -e $REPLY/index.html ]]':)

	## Find files with size == 0 and send a mail
	files=(*/(ND.L0m+0m-2)) > (( $#files > 0 )) && print -rl -- $files \| mailx -s "empty files" foo@bar.tdl

	## Print out all of the files in that directory in 2 columns
	print -rC2 -- ${1:[...]}/*(D:t)
	# ^- number ob columns
	# or - if you feel concerned about special characters - use
	list=(${1:[...]}/*(ND:t))
	(($#list)) && print -rC2 -- ${(V)list}

	## Show data to really binary format
	zsh -ec 'while {} {printf %.8x $n;repeat 8 \
	> {read -ku0 a printf \ %.8d $(([##2]#a))};print;((n+=8))}' < binary

	## A User's Guide to the Z-Shell /5.9: Filename Generation and Pattern Matching
	# find all files in all subdirectories, searching recursively, which have a given
	# name, case insensitive, are at least 50 KB large, no more than a week old and
	# owned by the root user, and allowing up to a single error in the spelling of
	# the name. In fact, the required expression looks like this:
	ls **/(#ia1)name(LK+50mw-1u0)

	## find all the empty directories in a tree
	for f in **/(/l2); do foo=($f/*(N)); [[ -z $foo ]] && print $f; done
	# Note:Since Zsh 4.2.1(?) the glob qualifier F indicates a non-empty directory.
	Hence (F) indicates all subdirectories with entries, (/^F) means all subdirectories with no
	entries.
	ls -ld *(/^F)

	## Use find(1) to find all directories except the ".svn" ones,
	# then use grep on all .c/.h/*.S files in each directory.
	setopt extendedglob
	grep pattern (^.svn/)#*.[xhS](.) # skips dot files and dot directories
	# or - without Zsh
	find . -type d ! -name .svn \| sed 's/./\\&/g;s\|.\|grep whatever &/.[xhS]\|' \| sh

	## Quote from Usenet
	# > I need to write a script that searches through a folder on my Linux
	# > home server and copies only files where the width is greater than the
	# > height, but it also needs to flatten the directory structure and
	# > rename files as it copies. So the first picture found may be several
	# > directories deep in the source but this should be copied to the root
	# > of the SD card and named say 00000001.JPG and the next file found
	# > where width > height should be copied and renamed 00000002.JPG.
	width_greater_than_height() {
	local w h
	identify -format '%w %h' ${1-$REPLY} \|
	read w h && ((w > h))
	}
	typeset -Z8 i=0
	setopt extendedglob
	for f (*/.(#i)jp(e\|)g(D.+width_greater_than_height)) {
	((i++))
	cp -- $f /path/to/dest/$i.JPG
	}

	# source: https://strcat.de/zsh/#tipps