bash

I’m playing around with bash and trying to understand how it thinks. I manage a bunch of servers so I wrote some aliases and functions to help me manage them. In my .profile or my .bash_profile I added a line to run the shell script that helps me do things. The last line is:

. ~/.bash_config

If you make changes to this file, you can reload your profile and see the changes by running:

source ~/.profile

I found a bunch of .bash_profile’s online and used some of the ideas from them. The best one is from Nathaniel Landau. I kept his basic structure and lots of his aliases. I also added a bunch of stuff people might be interested in. I left in a lot of stuff that I later rewrote so people learning bash can see my thought process as I developed the script.


# ---------------------------------------------------------------------------
# .bash_config
# Description: BASH configurations and aliases
# Called from .profile or .bash_profile with . ~/.bash_config
# Sections:
# 1. Environment Configuration
# 2. Make Terminal Better (remapping defaults and adding functionality)
# 3. File and Folder Management
# 4. Searching
# 5. Process Management
# 6. Networking
# 7. System Operations & Information
# 8. Web Development
# 9. Reminders & Notes
#
# Source: http://natelandau.com/my-mac-osx-bash_profile/
# Modified extensively - January 2014
# ---------------------------------------------------------------------------

# -------------------------------
# 1. ENVIRONMENT CONFIGURATION
# -------------------------------

# Change Prompt
# ------------------------------------------------------------
# export PS1="________________________________________________________________________________
\n| \w @ \h (\u) \n| => "
# export PS2="| => "
# \e[ - Indicates the beginning of color prompt
# x;ym - Indicates color code. Use the color code values mentioned below.
# \e[m - indicates the end of color prompt
# \e works on Ubuntu and in the OSX prompt, but not in echo commands on OSX use \033 instead
# Normal Colors
BLACK='\033[0;30m' # Black
RED='\033[0;31m' # Red
GREEN='\033[0;32m' # Green
YELLOW='\033[0;33m' # Yellow
BLUE='\033[0;34m' # Blue
PURPLE='\033[0;35m' # Purple
CYAN='\033[0;36m' # Cyan
WHITE='\033[0;37m' # White

# Bold - Change 0; to 1;
B_BLACK='\033[1;30m' # Black
B_RED='\033[1;31m' # Red
B_GREEN='\033[1;32m' # Green
B_YELLOW='\033[1;33m' # Yellow
B_BLUE='\033[1;34m' # Blue
B_PURPLE='\033[1;35m' # Purple
B_CYAN='\033[1;36m' # Cyan
B_WHITE='\033[1;37m' # White

NC='\033[m' # No Color - Reset color prompt

# Make it clear in the prompt which system I’m on
# localName=$(echo $HOSTNAME | cut -d. -f 2); # Pull out the local part of the HOSTNAME
if [ "$HOSTNAME" = "server" ]; then
hostColor=$B_RED;
elif [ "$HOSTNAME" = "dave" ]; then
hostColor=$B_PURPLE;
elif [ "$HOSTNAME" = "don" ]; then
hostColor=$B_CYAN;
# Mac $HOSTNAME has .local appended, cut it out
elif [ $(echo $HOSTNAME | cut -d. -f 2) = "local" ]; then
hostColor=$B_BLACK;
else
hostColor=$B_GREEN;
fi
# Colors are in {} just to be clear, even though \ is not a valid variable character.
# NC doesn’t need to be in {} since it is followed by a space.
export PS1="${B_BLUE}\u@${hostColor}\h: ${B_GREEN}\w$NC $ "

# Set Paths
# ------------------------------------------------------------
# export PATH="$PATH:/usr/local/bin/"
# export PATH="$PATH:/usr/local/git/bin:/sw/bin/:/usr/local/bin:/usr/local/:/usr/local/sbin:/usr/local/mysql/bin"

# Set Default Editor (change 'Nano' to the editor of your choice)
# ------------------------------------------------------------
export EDITOR=/usr/bin/vim
if [ "$HOSTNAME" = "Dave" ]
then
export EDITOR=/usr/bin/nano
fi

# Keep the history file around forever
export HISTSIZE=10000
export HISTFILESIZE=1000000000

# Set default blocksize for ls, df, du
# from this: http://hints.macworld.com/comment.php?mode=view&cid=24491
# ------------------------------------------------------------
export BLOCKSIZE=1k

# Add color to terminal
# from http://osxdaily.com/2012/02/21/add-color-to-the-terminal-in-mac-os-x/
# ------------------------------------------------------------
export CLICOLOR=1
# export LSCOLORS=ExFxBxDxCxegedabagacad

export TZ=America/Los_Angeles

# -----------------------------
# 2. MAKE TERMINAL BETTER
# -----------------------------
# Override an alias with command e.g. command cp file1 file2
# -i is the interactive flag, -v is the verbose flag
alias cp='cp -iv' # -i warns before overwriting
alias mv='mv -iv' # -i warns before overwriting
alias mkdir='mkdir -pv' # -p Create intermediate directories as required
mcd () { mkdir -p "$1" && cd "$1"; } # Makes new Dir and jumps inside

alias ll='ls -FGlAhp' #
alias less='less -FSRXc' # Preferred 'less' implementation

cd() { builtin cd "$@"; ll; } # Always list directory contents upon 'cd'
alias cd..='cd ../' # Go back 1 directory level (for fast typers)
alias ..='cd ../' # Go back 1 directory level
alias ...='cd ../../' # Go back 2 directory levels
alias .3='cd ../../../' # Go back 3 directory levels
alias .4='cd ../../../../' # Go back 4 directory levels
alias .5='cd ../../../../../' # Go back 5 directory levels
alias .6='cd ../../../../../../' # Go back 6 directory levels
alias ~="cd ~" # Go Home

alias which='type -all' # Find executables
alias path='echo -e ${PATH//:/\\n}' # Echo all executable Paths

#
# OSX specific aliases and commands
#
alias f='open -a Finder ./' # Opens current directory in OSX Finder

trash () { command mv "$@" ~/.Trash ; } # Moves a file to the OSX trash
ql () { qlmanage -p "$*" >& /dev/null; } # Opens any file in OSX Quicklook Preview
alias DT='tee ~/Desktop/terminalOut.txt' # Pipe content to file on OSX Desktop

# lr: Full Recursive Directory Listing
# ------------------------------------------
alias lr='ls -R | grep ":$" | sed -e '\''s/:$//'\'' -e '\''s/[^-][^\/]*\//--/g'\'' -e '\''s/^/ /'\'' -e '\''s/-/|/'\'' | less'

# mans: Search manpage given in agument '1' for term given in argument '2' (case insensitive)
# displays paginated result with colored search terms and two lines surrounding each hit.
# Example: mans mplayer codec
# --------------------------------------------------------------------
mans () {
man $1 | grep -iC2 --color=always $2 | less
}
alias mansearch='mans'
# showa: to remind yourself of an alias (given some part of it)
# ------------------------------------------------------------
showa () { /usr/bin/grep --color=always -i -a1 $@ ~/Library/init/bash/aliases.bash | grep -v '^\s*$' | less -FSRXc ; }

# -------------------------------
# 3. FILE AND FOLDER MANAGEMENT
# -------------------------------

zipf () { zip -r "$1".zip "$1" ; } # Create a ZIP archive of a folder
alias numFiles='echo $(ls -1 | wc -l)' # Count of non-hidden files in current dir
alias make1mb='mkfile 1m ./1MB.dat' # Creates a file of 1mb size (all zeros)
alias make5mb='mkfile 5m ./5MB.dat' # Creates a file of 5mb size (all zeros)
alias make10mb='mkfile 10m ./10MB.dat' # Creates a file of 10mb size (all zeros)

# extract: Extract most known archives with one command
# ---------------------------------------------------------
extract () {
if [ -f $1 ] ; then
case $1 in
*.tar.bz2) tar xjf $1 ;;
*.tar.gz) tar xzf $1 ;;
*.bz2) bunzip2 $1 ;;
*.rar) unrar e $1 ;;
*.gz) gunzip $1 ;;
*.tar) tar xf $1 ;;
*.tbz2) tar xjf $1 ;;
*.tgz) tar xzf $1 ;;
*.zip) unzip $1 ;;
*.Z) uncompress $1 ;;
*.7z) 7z x $1 ;;
*) echo "'$1' cannot be extracted via extract()" ;;
esac
else
echo "'$1' is not a valid file"
fi
}

# ---------------------------
# 4. SEARCHING
# ---------------------------

alias qfind="find . -name " # qfind: Quickly search for file
ff () { /usr/bin/find . -name "$@" ; } # ff: Find file under the current directory
ffs () { /usr/bin/find . -name "$@"'*' ; } # ffs: Find file whose name starts with a given string
ffe () { /usr/bin/find . -name '*'"$@" ; } # ffe: Find file whose name ends with a given string

# spotlight: Search for a file using MacOS Spotlight's metadata
# -----------------------------------------------------------
spotlight () { mdfind "kMDItemDisplayName == '$@'wc"; }

#
alias h='history' # Shortcut for history
hist() { history | grep $1; } # Find a command in the history, e.g hist man

# ---------------------------
# 5. PROCESS MANAGEMENT
# ---------------------------

# findPid: find out the pid of a specified process
# -----------------------------------------------------
# Note that the command name can be specified via a regex
# E.g. findPid '/d$/' finds pids of all processes with names ending in 'd'
# Without the 'sudo' it will only find processes of the current user
# -----------------------------------------------------
findPid () { lsof -t -c "$@" ; }

# memHogsTop, memHogsPs: Find memory hogs
# -----------------------------------------------------
alias memHogsTop='top -l 1 -o rsize | head -20'
alias memHogsPs='ps wwaxm -o pid,stat,vsize,rss,time,command | head -10'

# cpuHogs: Find CPU hogs
# -----------------------------------------------------
alias cpu_hogs='ps wwaxr -o pid,stat,%cpu,time,command | head -10'

# topForever: Continual 'top' listing (every 10 seconds)
# -----------------------------------------------------
alias topForever='top -l 9999999 -s 10 -o cpu'

# ttop: Recommended 'top' invocation to minimize resources
# ------------------------------------------------------------
# Taken from this macosxhints article
# http://www.macosxhints.com/article.php?story=20060816123853639
# ------------------------------------------------------------
alias ttop="top -R -F -s 10 -o rsize"

# my_ps: List processes owned by my user:
# ------------------------------------------------------------
my_ps() { ps $@ -u $USER -o pid,%cpu,%mem,start,time,bsdtime,command ; }

# ---------------------------
# 6. NETWORKING
# ---------------------------

# Log in to other systems

id=$(who am i | cut -d\ -f 1)
server='192.168.194.220'
dave='192.168.201.11'
don='192.168.102.113'
purple='purple.aserver.com'

# Update the list of servers if you add one. It is used on connect and scp functions
servers=(server dave don purple)

# The commented out aliases and functions are experiments with different ways to use aliases and functions

# With the id placed in the alias, not generalizable
# alias server='ssh myloginid@192.168.194.220'

# Find the userID from login info
# alias server='ssh $(who am i | cut -d\ -f 1)@192.168.194.220'

# Make the userID an alias
# alias myID='who am i | cut -d\ -f 1'
# alias server='ssh "echo $(myID)"@192.168.194.220'
# alias server='ssh $(myID)@192.168.194.220'

# Make the userID a variable and use it later in the function
# server() { id=$(who am i | cut -d\ -f 1); ssh $id@192.168.194.220; }

# Make the userID a variable in the shell script and use it in an alias or function
# $id can’t be local since isn’t called until the alias or function is invoked.
# id=$(who am i | cut -d\ -f 1)
# alias server='ssh $id@192.168.194.220'
# server() { ssh $(myID)@192.168.194.220 ; }

# Using the select conditional to pick a server
# This example shows how a case statement and $REPLY can be used
# It can be generalized so that answers aren’t hard coded
whichserver() {
# We don’t need the list outside this function. Making it local assures that we don’t clobber a previous alias with the same name
local serverlist=(server dave don purple)
PS3='Select a server. '

select srv in ${serverlist[@]} "Quit"; do # the @ expands all the elements of the array into separate words

case "$REPLY" in
# It would be nice if you could do this, but you can’t put anything in a case statement that isn’t one of the cases
# arrayitem=$(( ${#serverlist[@]}+1 ))
1 )
echo "Connecting to ${serverlist[$REPLY-1]}"; ssh "$id@$server" ;;
2 )
echo "Connecting to ${serverlist[$REPLY-1]}"; ssh "$id@$dane" ;;
3 )
echo "Connecting to ${serverlist[$REPLY-1]}"; ssh "$id@$dane" ;;

# The last option is quit. (( )) is arithmetic evaluation. # counts the number of items in the array.
$(( ${#serverlist[@]}+1 )) )
echo "No server selected.";
esac

break

done
}

# Here's the same code using an eval to run the alias

connect() {
# Requires an array called servers that has IP addresses or domain names.
# It is defined when aliases are defined at the beginning of this script.
if [ -z "$1" ]; then

PS3='Select a server. '
select srv in ${servers[@]} "Quit"; do # the @ expands all the elements of the array into separate words

if [ "$REPLY" -lt $(( ${#servers[@]}+1 )) ]; then
echo "Connecting to ${servers[$REPLY-1]}"
ssh ${!servers[$REPLY-1]}
else
echo "No server selected.";
fi

break

done
else
echo "Connecting to $1"
ssh ${!1}
fi
}

# Share .bash_config. Requires . ~/.bash_config in .bash_profile
share() {

# This works if you want to list out each server
# scp .bash_config ${id}@${server}:.bash_config
# scp .bash_config ${id}@${dane}:.bash_config
# scp .bash_config ${id}@${dan}:.bash_config

for serv in "${servers[@]}"; do
echo "Connecting to $serv"
scp .bash_config ${id}@${!serv}:.bash_config
done
}

alias myip='curl ip.appspot.com' # Use Google’s AppSpot site to find this machine’s public facing IP Address
alias netCons='lsof -i' # Show all open TCP/IP sockets
alias flushDNS='dscacheutil -flushcache' # Flush out the DNS Cache
alias lsock='sudo /usr/sbin/lsof -i -P' # Display open sockets
alias lsockU='sudo /usr/sbin/lsof -nP | grep UDP' # Display only open UDP sockets
alias lsockT='sudo /usr/sbin/lsof -nP | grep TCP' # Display only open TCP sockets
alias ipInfo0='ipconfig getpacket en0' # Get info on connections for en0
alias ipInfo1='ipconfig getpacket en1' # Get info on connections for en1
alias openPorts='sudo lsof -i | grep LISTEN' # All listening connections
alias showBlocked='sudo ipfw list' # All ipfw rules inc/ blocked IPs

# ii: display useful host related informaton
# -------------------------------------------------------------------
# -e enable interpretation of backslash escapes

ii() {
## \e works on Ubuntu but not recognized on OSX, must use \033
## Didn’t work since colors weren’t defined. Now they are.
## local RED='\033[0;31m' # Red
## local NC="\033[0m" # Color Reset
echo -e "\nYou are logged on to $HOST"
echo -e "\nAdditional information: " ; uname -a
echo -e "\n${RED}Users logged on:${NC} " ; w -h
echo -e "\n${RED}Current date :${NC} " ; date
echo -e "\n${RED}Machine stats :${NC} " ; uptime
echo -e "\n${RED}Current network location :${NC} " ; scselect
echo -e "\n${RED}Public facing IP Address :${NC} " ;myip
#echo -e "\n${RED}DNS Configuration:${NC} " ; scutil --dns
echo
}

# ---------------------------------------
# 7. SYSTEMS OPERATIONS & INFORMATION
# ---------------------------------------

alias mountReadWrite='/sbin/mount -uw /' # mountReadWrite: For use when booted into single-user

# cleanupDS: Recursively delete .DS_Store files
# -------------------------------------------------------------------
alias cleanupDS="find . -type f -name '*.DS_Store' -ls -delete"

# finderShowHidden: Show hidden files in Finder
# finderHideHidden: Hide hidden files in Finder
# -------------------------------------------------------------------
alias finderShowHidden='defaults write com.apple.finder ShowAllFiles TRUE'
alias finderHideHidden='defaults write com.apple.finder ShowAllFiles FALSE'

# cleanupLS: Clean up LaunchServices to remove duplicates in the "Open With" menu
# -----------------------------------------------------------------------------------
alias cleanupLS="/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user && killall Finder"

# screensaverDesktop: Run a screensaver on the Desktop
# -----------------------------------------------------------------------------------
alias screensaverDesktop='/System/Library/Frameworks/ScreenSaver.framework/Resources/ScreenSaverEngine.app/Contents/MacOS/ScreenSaverEngine -background'

# ---------------------------------------
# 8. WEB DEVELOPMENT
# ---------------------------------------

alias apacheEdit='sudo $EDITOR /etc/httpd/httpd.conf' # Edit httpd.conf
alias apacheRestart='sudo service apache2 restart' # Restart Apache
alias mySQLRestart='sudo service mySQL restart' # Restart mySQL
alias editHosts='sudo $EDITOR /etc/hosts' # Edit /etc/hosts file
alias taile='tail -f /var/log/php_error.log' # Tails PHP error logs
alias apacheLogs="less +F /var/log/apache2/error_log" # Shows apache error logs
httpHeaders () { /usr/bin/curl -I -L $@ ; } # httpHeaders: Grabs headers from web page

# httpDebug: Download a web page and show info on what took time
# -------------------------------------------------------------------
httpDebug () { /usr/bin/curl $@ -o /dev/null -w "dns: %{time_namelookup} connect: %{time_connect} pretransfer: %{time_pretransfer} starttransfer: %{time_starttransfer} total: %{time_total}\n" ; }

# ---------------------------------------
# 9. REMINDERS & NOTES
# ---------------------------------------

# Things I Can’t Remember
ticr() {
echo -e "\n${B_PURPLE}Things I Can’t Remember$NC"
# Ubuntu update commands
echo -e "\n${B_BLACK}safe-upgrade is preferred$NC"
echo -e "sudo aptitude safe-upgrade"

echo -e "\n${B_BLACK}If safe-upgrade doesn’t work you can do it manually$NC"
echo -e "sudo apt-get update"
echo -e "sudo apt-get upgrade"

echo -e "\n${B_BLACK}Sometimes a reboot is required after an update$NC"
echo -e "sudo reboot"

echo -e "\n${B_BLACK}scp a file e.g public key$NC"
echo -e "scp ./.ssh/RSA_KEY.pub myloginid@198.199.102.113:/home/myloginid/.ssh/authorized_keys"
}

Bash: Using an alias in an alias

I’ve been helping set up some VPSs (Virtual Private Server) and at the moment they don’t have domain names assigned. I can use the history command to find the right IP address to ssh in but that can be cumbersome. So I decided to write an alias for each server. These lines are in my extended bash config file that is called when my .profile runs.

My login is the same on each server so I could hard code this, but I made it general so I can share it with other users. I don’t like to hard code things so I thought I’d let bash find my user id and then use it in the ssh command. My first thought was to just create an alias for my login and use it in an alias for each server. But I couldn’t get it to work. I tried using just the alias since examples of creating aliases seem to work this way with builtin commands. Then I thought that maybe I need to escape the alias so that bash knows that it should process it.


alias myID='who am i | cut -d\  -f 1'
alias myserver='ssh myID@192.245.184.221'      #Doesn’t work
alias myserver='ssh $(myID)@192.245.184.221'   #Works fine

It turns out that the second line works, but I did had a problem with aliases being set and it didn’t work for me. So I started playing around with things that did work and making small adjustments. FYI, One thing you need to do if you redefine aliases and functions is to make sure that you clear out the old ones. If you don’t then you may not be running the function you thought you were or you could be running an alias when you thought you were running a function.

You can use unset to remove them from memory. Use the -f flag for functions.


unset myID
unset -f dave

For myserver, I put the alias command in parens and prefixed it with a $. Bash executes this first and then uses it in the ssh command. If you don’t do this, bash thinks that the first argument for ssh is ‘who’ and fails. That worked, but I don’t like the idea of having duplicate code in login alias. So I thought I’d try a function. In the first function, I define a variable and then use it. The third function looks an awful lot like a failed alias in the example above, but since it is a function, it works. I think what is happening is that when bash sees $(myID) it thinks, I should process whatever is inside the parens. So it finds the alias and runs it.


#   Log in to other systems
alias myID='who am i | cut -d\  -f 1'

alias myserver='ssh $(who am i | cut -d\  -f 1)@192.245.184.221'
dave() { id=$(who am i | cut -d\  -f 1); ssh $id@192.233.221.11; }
dana()  { ssh $(myID)@192.149.142.163 ; }

alias bigserver='ssh "echo $(myID)"@192.255.174.220'

It finally occurred to me that the .profile script is a full blown shell script. So that means I can use variables in it. I define an id variable that is the result of the shell executing the commands that are in it. When the .profile is run, bash assigns id to my login. Then I can use it anywhere I want with $id. I don’t need to use ${id} since my login is one word and since the @ cannot be in a variable name, bash knows to stop processing when it hits the @. This is what I wanted to do with aliases. I thought about making it a local variable since I don’t need it to hang around outside of this script. But the alias isn’t resolved until it is used, so it needs to resolve the variable when it is called.


#   Log in to other systems
id=$(who am i | cut -d\  -f 1)
alias myserver='ssh $id@192.245.184.221'
alias dave='ssh $id@192.233.221.11'
alias dana='ssh $id@192.149.142.163'

I started playing around with aliases again and got strictly aliases to work as well.


#   Log in to other systems
alias myID='who am i | cut -d\  -f 1'
alias myserver='ssh $(myID)@192.245.184.221'
alias dave='ssh $(myID)@192.233.221.11'
alias dana='ssh $(myID)@192.149.142.163'

Update: I was playing with printenv and it turns out that one of the environment variables is LOGNAME. So you can replace the $id with $LOGNAME in the code above.

Notes on setting up a server.

I’m setting up a new Ubuntu server and while most of the defaults are fine, there are some things that I need to adjust. I have a very shallow understanding of this stuff, so there could be better and more secure ways to do this, but this works for me.

Disallow access to PHP include files

There isn’t any reason that people need to see the include files that I use in my websites. You could name them .inc.php so that the raw code isn’t available, but that’s not very elegant, and outsiders can still access the file. There isn’t anything particularly sensitive in them, but by themselves, they don’t display correctly. So I added a few lines to my /etc/apache2/apache2.conf file. Just below the section that disallows viewing .htacess files.


#
# The following lines prevent .htaccess and .htpasswd files from being 
# viewed by Web clients. 
#
<Files ~ "^\.ht">
    Order allow,deny
    Deny from all
    Satisfy all
</Files>

# The following lines prevent .inc files from being
# viewed by Web clients.
#
<Files ~ "\.inc$">
    Order allow,deny
    Deny from all
</Files>
#

Prevent directory browsing

If you have a bunch of images in a directory, then anyone who wants can view all of them just by looking at the web page source and putting the directory name after your URL. I’d rather they not do that, so I restrict listing of the files by adding this line to my /etc/apache2/httpd.conf file. On my default Ubuntu install this file is empty.


Options Includes FollowSymLinks MultiViews

Restart Apache for the changes to take effect.

Alternate method to prevent directory browsing

If you want to prevent directory browsing in just one directory and either don’t want to change the whole site or don’t have access to the files named above, add this line to your .htaccess file.


Options -Indexes

Probably don’t have to restart Apache for changes to take effect.

Prevent Directory Browsing on a Per Site Basis

Changing the httpd.conf file will change the behavior of all sites on your server. If you want to change the behavior of just one site, edit its file in /etc/apache2/sites-avalilable. Find the line that has Options FollowSymLinks in it and if it has Indexes in it, delete it. This is what the default Ubuntu install has.


  <Directory /var/www/>
    Options Indexes FollowSymLinks MultiViews
    AllowOverride None
    Order allow,deny
    allow from all
  </Directory>

Probably do have to restart Apache for changes to take effect.

Prevent access to your include directory

Add this to your site’s file in /etc/apache2/sites-avalilable.


#<Directory /www/MySite/include.php>
#    Deny from all
#</Directory>

Show an error document instead of the default 404 error

Create a normal php document with your sites navigation and a message that says the file can’t be found and maybe you can find it with the nav menus. Add this to your site’s file in /etc/apache2/sites-avalilable. And while you are at it, there is no reason you need to tell anyone that they don’t have permission to see a particular file, just tell them it’s not found, so add the same line for a 403 error. I take them back to the main page and display the missing file in the main page.


ErrorDocument 404 /index.php?p=missing
ErrorDocument 403 /index.php?p=missing

Removing subviews from a view.

In my apps, I use swipe gestures to move to the next screen. The old stuff is animated off to the left and the new stuff animates in from the right. If the user rotates the device, I need to remove the elements of the view from the main view and redisplay them in the new orientation. I also need to remove the animations if they are occurring. I have lots of different layouts, but each layout has this method in it. (The contents vary a bit.)

I first remove the animations. Then I remove the views from the main view. Then I set the views to nil to make sure their resources are released.


- (void)removeAllObjectsFromParentView {
    [self.wordView.layer removeAllAnimations];
    [self.categoryView.layer removeAllAnimations];
    
    [self.wordView removeFromSuperview];
    [self.categoryView removeFromSuperview];
   
    self.wordView = nil;
    self.categoryView = nil;
}

All of the subviews of wordView and categoryView will be removed and released when the parent view is removed and released.

Pick a random color in iOS

In one of my methods I wanted to put randomly colored text on the screen. I put this class method in my Utilities.m class.


#define ARC4RANDOM_MAX      0x100000000
+ (UIColor *) randomColor {
    CGFloat red =  (CGFloat)arc4random()/ARC4RANDOM_MAX;
    CGFloat blue = (CGFloat)arc4random()/ARC4RANDOM_MAX;
    CGFloat green = (CGFloat)arc4random()/ARC4RANDOM_MAX;
    return [UIColor colorWithRed:red green:green blue:blue alpha:1.0];
}

To set the color, just call


label.textColor = [Utilities randomColor];