Some notes I made while setting up ZSH for the first time

zsh-notes.txt

ZSH and Misc Command Line Notes
===============================

Handy Man Pages
---------------

zshexpn         Expansion and substitution
zshmisc         "Everything and then some"


Command Line Editing
--------------------

ESC-.           Insert last argument of previous history line. Repeat to go further back.
ESC-q           Delete line and insert it again on next prompt to issue interim command.
ESC-'           Quotes whole line
ESC-RETURN      Insert literal newline. Easier to edit long lines.


Directories
-----------

cd OLD NEW      Swap out OLD with NEW in current full path and try to cd there
DIRNAME         cd DIRNAME
cd -<TAB>       Select dir from stack
mv FILE ~2      Move FILE to entry 2 on dir stack

### Aliases for 'dirs' and 'cd' (Auto-loaded from ~/.oh-my-zsh/lib/directories.zsh)

d               Show 'dirs' directory stack with index numbers.
1,2,3,...       cd to the corresponding entry in the directory stack
-               cd back and forth between the top two dirs in the stack.
..              cd back one level
...             cd back two levels



File Globbing
-------------

Use parentheses for grouping.

<5-12>          Numbers from 5 to 12
<5->            Numbers from 5 and up
<-12>           Numbers up to 12
<->             Any number
*               Any string
?               Any character
[...]           Any character or character range in set
[^...]          Inverted set
x|y             x or y. Must be in parentheses.
x#              Zero or more occurrences of x
x##             One or more occurrences of x
**/             Recursive match for directories. Shorthand for (*/)#
***/            Like **/ but also follows symbolic links.
pat1~pat2       Matches if pattern 1 matches and pattern 2 does not match

### Globbing Qualifiers

Put at the end of the pattern, enclosed in parentheses.

/               Directories
.               Plain files
@               Symbolic links
*               Executable files
m[Mwhm][-|+]n   Modified less/more than n days/months/weeks/hours/minutes ago
L[kKmM][-|+]n   File size less/more than n bytes/kilobytes(k|K)/megabytes(m|M)

### Examples

**/*ViewController.[hm](m-5)      All view controller files modified in the last 5 days
*(.L0)                            Zero-length regular files
**/*(.Lm+10)                      Files larger than 10 MB anywhere in hierarchy
*(m0)                             Files modified today

Expansions
----------
{x,y,z}         x y z
{5..8}          5 6 7 8
=foo            Full path of file foo

History
-------

!!              Previous command
!n              History command number n
!-n             Current command minus n
!str            Most recent command starting with str
!?str[?]        Most recent command containing str

!^              First argument of previous command
!$              Last argument of previous command
!:n             N'th argument of previous command
!*              All arguments of last command

!!:s/x/y/       Last command with first x replaced by y
!!:gs/x/y/      Last command with all x replaced by y

r               Repeat last command
r x=y           Repeat last command with x replaced by y

Misc
----

<(COMMAND)      Readable pipe containing the output of COMMAND.
                Example: ack <(ls DIR1) <(ls DIR2)   # See files not in both dirs
$#array         Number of elements in array

Snippets
--------

### Read a file into a variable

  $ var="$(<file)"

  
### Copy a directory structure recursively without data/files

  $ dirs=(**/*(/))
  $ cd -- $dest_root
  $ mkdir -p -- $dirs


### Quick for-each on files in a dir

  $ for f (*) print -- $f


### Random numbers

  $ echo $[${RANDOM}%1000]     # random between 0-999
  $ echo $[${RANDOM}%11+10]    # random between 10-20
  $ echo ${(l:3::0:)${RANDOM}} # N digits long (3 digits)


### Random array element

  $ array = (*)
  $ print $array[$RANDOM%$#array+1]


### Ping a range of hosts

  $ for i in {1..254}; do ping -c 1 192.168.1.$i; done


### Add numerical prefix to all files using the default sort order

  $ i=1; for j in *; do mv $j $i.$j; ((i++)); done


### Change extension on all matching files

Remember: zmv needs the glob patterns. Not the shell's expansion of them. Hence the quotes

  $ zmv '(*).text' '$1.txt'         # Equivalent lines. Use match group.
  $ zmv -W '*.text' '*.txt'         # Equivalent lines. Use wildcard to reference flag.
  $ for f (*.text) mv $f $f:r.txt   # :e :r :h :t 

### Remove leading zeros from file extension

Remember: zmv needs the glob patterns. Not the shell's expansion of them. Hence the quotes

  $ ls
  filename.001  filename.003  filename.005  filename.007  filename.009
  filename.002  filename.004  filename.006  filename.008  filename.010
  $ zmv '(filename.)0##(?*)' '$1$2'
  $ ls
  filename.1  filename.10  filename.2  filename.3  filename.4  filename.5  filename.6 ...


### Lower/uppercase all matching files/dirs

  $ zmv '(*)' '${(L)1}' # lowercase
  $ zmv '(*)' '${(U)1}' # uppercase


### Rename pic1.jpg, pic2.jpg, ... to pic0001.jpg, pic0002.jpg, ...

  $ zmv 'pic(*).jpg' 'pic${(l:4::0:)1}.jpg'           # In current dir
  $ zmv '(**/)pic(*).jpg' '$1/pic${(l:4::0:)2}.jpg'   # Recursively