coderofsalvation

# flexible xmessage (uses xmessage or gmessage) or printf for printing messages

function x11message()
{   #prints a message using xmessage || gxmessage
    [ -z "$1" ] && return 1
    XMESSAGE=$(command -v gxmessage 2>/dev/null) || XMESSAGE=$(command -v xmessage 2>/dev/null)
    MESSAGE="$(expr "$0" : '.*/\([^/]*\)'): $*"
    printf "%s\\n" "$MESSAGE" | fold -s -w ${COLUMNS:-80} >&2
    if [ -n "$DISPLAY" ] && [ -n "$XMESSAGE" ]; then
        printf "%s\\n" "$MESSAGE" | fold -s -w ${COLUMNS:-80} | $XMESSAGE -center -file -

coderofsalvation

# checks if string is valid email 

function isemail(){
  emailTest=$(echo "${1}" |  grep '^[a-zA-Z0-9._%+-]*@[a-zA-Z0-9]*[\.[a-zA-Z0-9]*]*[a-zA-Z0-9]$')
  if [[ "$emailTest" != "" ] ; then return 0; else return 1; fi
}

coderofsalvation

# returns 0 if parameter is a valid ip4 address, non-zero otherwise

function isvalidip4()
{   #return 0 if parameter is a valid ip4 address, non-zero otherwise
    #https://groups.google.com/forum/#!original/comp.unix.shell/NDu-kAL5cHs/7Zpc6Q2Hu5YJ
    [ -z "$1" ] && return 1

    case "$*" in
        ""|*[!0-9.]*|*[!0-9]) return 1 ;;
    esac

coderofsalvation

# returns 0 if parameter is a valid network interface, 1 otherwise

function isvalidinterface()
{   
    [ -z "$1" ] && return 1
    ip addr show | grep "$1": >/dev/null && return 0
    return 1
}

coderofsalvation

# uploads images e too imgur.com, returns url on success, 1 otherwise
# @dependancy curl 

function uploadimg()
{ 
    [ -z "$1" ] && return 1

    for img
    do
        if [ -f "$img" ] ; then

coderofsalvation

# replaces a string with another string
# @param string source string
# @param string search string
# @param string replacement string"
# usage: result="$(str_replace "foo bar" "foo" "hi")"

function str_replace()
{
    [ -z "$1" ] && return 1
    [ -z "$2" ] && return 1

coderofsalvation

# prints out the length of a string
# @param string input

function strlen()
{
    [ -z "$1" ] && return 1
    printf "%s\\n" "${#1}"
}

coderofsalvation

# prints out the duplicate parts of 2 strings
# @param string input1
# @param string input2

function stroverlap()
{
    [ -z "$1" ] && return 1
    [ -z "$2" ] && return 1
    printf "%s\\n" $@ | awk 'x[$0]++'
}

coderofsalvation

# prints out the differences of two strings
# @param string input1
# @param string input2

function strdiff()
{
    [ -z "$1" ] && return 1
    [ -z "$2" ] && return 1

    set -x

coderofsalvation

# converts a string to lower characters
# @param string input

function strtoupper()
{   
    [ -z "$1" ] && return 1
    printf "%s\\n" "$@" | tr 'abcdefghijklmnopqrstuvwxyz' 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' # tr '[:upper:]' '[:lower:]'
}