coderofsalvation

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

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

coderofsalvation

# remove lines with certain strings from crontab
# @param string search

rmcron()
{   #remove cron job, returns 1 on error
    [ -z "$1" ] && return 1
    crontab -l | grep -v "$1" | crontab
}

coderofsalvation

# check if port is a num and if it's privated (<1025), returns 0 on success, 1 otherwise
# @param int portnumber

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

    printf "%s\\n" "$1" | grep -v "[^0-9]" >/dev/null
    if [ $? -eq 0 ]; then
        [ $1 -gt 0 ] && [ $1 -lt 1025 ] && return 0 || return 1

coderofsalvation

# returns 0 if string is a number
# @param string input

function isnumber()
{   #look for a number, returns 0 on success, 1 otherwise
    [ -z "$1" ] && return 1
    printf "%s\\n" "$@" | grep -v "[^0-9]" >/dev/null
}

coderofsalvation

# compare the dates of two files, return true (0) if file1 has
# been modified more recently otherwise 1
# @param string file1
# @param string file2

function is_newer()
{   
    [ $# -ne 2 ] && return 1
    if [ ! -f $1 ] || [ ! -f $2 ]; then
        return 1       # No

coderofsalvation

# returns 0 if monitor is attached

function ismonitorattached()
{
    xrandr | grep "^VGA" | grep " connected" >/dev/null && return 0
    xrandr | grep "^HDMI" | grep " connected" >/dev/null && return 0
    return 1
}

coderofsalvation

# detect a livecd system, return 0 on success, 1 otherwise


function islivecd()
    grep boot=live /proc/cmdline >/dev/null && return 0
    grep boot=casper /proc/cmdline >/dev/null && return 0
    return 1
}

coderofsalvation

# detect if arg is an empty file, returns 0 on sucess, 1 otherwise
# @param string file 

function isemptyfile()
{   [ -z "$1" ] && return 1
    if [ -f "$1" ] && [ X"$(wc -c "$1" | cut -d" " -f1)" = X"0" ]; then
        return 0
    else
        return 1
    fi

coderofsalvation

# return distro name in a lower string

function getdistro()
{   
    _distro_var_DIST_INFO="/etc/lsb-release"
    if [ -r "$_distro_var_DIST_INFO" ]; then
        . "$_distro_var_DIST_INFO"
    fi

    if [ -z "$DISTRIB_ID" ]; then

coderofsalvation

# print a stacktrace with a msg, exits with 1

function stacktrace()
{  
    if [ -n "$BASH" ]; then
        _die_var_frame=0
        while caller $_die_var_frame; do
            _die_var_frame=$(expr $_die_var_frame + 1);
        done
    fi