Stick up your best shell scripts

Cheating slightly - its perl, not bash.... but maybe someone will find it useful. In the sys admin line of work, you spend a lot of time watching logs - so this script colorises the output to make it easy to notice errors, exceptions, whatever...

You could use it like so: tail -f /var/log/mylogfile | color.pl

#!/usr/bin/perl

use Term::ANSIColor qw(:constants);
use Switch;

while( defined ($line = <STDIN>) )
{
    switch ($line)
    {
        ## Obviously, add your own regular expressions and colors here.... 
        case /Exception/           { print YELLOW, ON_RED,    "$line", RESET; }
        case /[Ee]rror/            { print YELLOW, ON_BLACK,  "$line", RESET; }
        case /Success/             { print GREEN, ON_BLACK,   "$line", RESET; }
        else                       { print WHITE, ON_BLACK    "$line", RESET; }
    }
}

If you need something more configurable, try http://kassiopeia.juls.savba.sk/~garabik/software/grc.html

Wife about to go into labour? Unsure how to help? What not write a bash script to time her contractions... (seemed like a good idea at the time...)

#!/bin/sh

STIME=-1
COUNTER=0

## Set these threshold parameters to whatever you want...

C_THRESH=2     ## More than 2 contractions...
P_THRESH=600   ## less than 10 mins apart...
D_THRESH=30    ## lasting at least 60 seconds each...

echo
echo "###################################################################################"
echo "##              L a b o u r   C o n t r a c t i o n   T i m e r                  ##"
echo "###################################################################################"
echo

while [ 1 == 1 ]
do
    echo -n "####: Press any key to start next contraction..."
    read

    ### OK, lets go...

    if [ $STIME -eq -1 ]
    then
        OTIME=`date +%s`
    else
        OTIME=$STIME
    fi

    PTIME=`date +%H:%M:%S`
    STIME=`date +%s`

    echo -n "####: Started - press any key to end..."
    read

    ## Work out details

    ETIME=`date +%s`

    DURATION=`expr $ETIME - $STIME`
    PERIOD=`expr $STIME - $OTIME`

    echo "INFO: Contraction Over - started at $PTIME ($PERIOD secs since last time) - lasted for $DURATION seconds"

    if [ $PERIOD -lt $P_THRESH -a $DURATION -gt $D_THRESH ]
    then
        COUNTER=`expr $COUNTER + 1`

        if [ $COUNTER -gt $C_THRESH ]
        then 
            echo "CRIT: Consistent frequency and duration *strongly* suggest hospital visit...."
        else
            echo "WARN: Frequency and duration suggest possible hospital visit...."
        fi
    else
        COUNTER=0
    fi
done

Sheeps wrote: »

I will have lost a little bit of faith in humanity and I'll worry for your children if you actually did this.

I worry for my children too, but hey, what you gonna do.... You can't pick your dad.

(Baby finally arrived today, after ~28 hours of irregular pre-hospital contractions, so the script worked out being very useful - given that wife was not very diligent at writing times down, but would happily press enter at the start and end of the contractions, until we left for hospital...)

To get us back OT - a short and sweet bash webserver....

while [ true ]; do echo "SERV: The time is `date`" | nc -l 8080; done

Connect to http://127.0.0.1:8080/ to check the output...

(in)famous!

http://www.reddit.com/r/programming/comments/akw7e/feeling_like_a_nerd_you_have_not_written_a_bash/

you need to use backticks and not quotation marks:

set x =`basename path/file.txt .txt` ; echo $x

Backticks do what you are intending, the line inside the ticks is executed and the output sent to your variable x.

Rob

RobbieM wrote: »

Jeeperss!! Thanks, I love u!! Everybody, give him some thanks!! backticks! brilliant! I knew there must be a way! Brilliant!

Well you can't say he's not appreciative. Makes up for all the times you supply an answer and receive no thanks .

A very simple one I put together just solely to download the videos from the speed demos archives easily ( http://speeddemosarchive.com/ ) - 1 command per set of videos per game
./<script name> <url of 1st video> <number of videos> <file name prefix>

#!/bin/bash

length=${#1}
url=$( echo $1 | cut -c1-$(expr $length - 6))
extension=$( echo $1 | cut -c$(expr $length - 3)-$length )

for i in $(seq 1 1 9)
do
wget -nc -O $3'_'$i$extension $url'0'$i$extension
done

for i in $(seq 10 1 $2)
do
wget -nc -O $3'_'$i$extension $url$i$extension
done

dioltas wrote: »

Here's a little script I wrote for picking 6 random lottery numbers between 1 and 49.

#!/bin/bash
    i=0
    while [ $i -lt 6 ];    do
            num=$(( ((`od -An -N2 -t u2 /dev/random`)%(49)) +1   ))
         
            instr=`echo $stra | grep -c " $num "`
    
            if [ $instr -eq 0 ]
                then
                stra=`echo $stra $num`
                let i=$i+1
            fi

        done  

    echo $stra

Don't think it's a very efficient way of checking for duplicates but it'll do for the purpose!

Fixed:

#!/bin/bash
i=0
while [ $i -lt 6 ]; do
    num=$(( ((`od -An -N2 -t u2 /dev/random`)%(49)) +1   ))
    instr=`echo $stra | grep -c " $num "`
    if [ $instr -eq 0 ]; then
        stra=`echo $stra $num`
        i=$(($i+1))
    fi
done  
echo $stra

Here is a simple script I wrote that backs up my home directory to my external hard drive, if it is connected and turned on, and keeps track of when the last backup was performed.

#!/bin/bash

EXT_HDD_PATH=/media/IOMEGA_HDD # path to your external storage device
BACKUP_DIR=$EXT_HDD_PATH/home_backup/ # name of directory on storage device that you want to backup to
TIME_FILE=$HOME/bin/last_backup.txt# name/location of file to keep track of when last backup was performed.

if [[ -e $EXT_HDD_PATH ]]
then

    if [[ ! -e $BACKUP_DIR ]]
    then mkdir $BACKUP_DIR
    fi

    rsync -qa $HOME $BACKUP_DIR
    
    date +%s > $TIME_FILE

fi

Then you can put this line in your .conkyrc file:

${color grey}Days since backup:$color ${exec echo $((($(date +%s)-$(cat ~/bin/last_backup.txt))/86400))}

Replacing the path with the path to your TIME_FILE (and the color settings with your own, of course), and conky will tell you how many days since you last backed up.

I wrote it with the intention of crontabing it to run once per day. When I run it from the command line, it appears as though some attributes (like symlinks in certain hidden files) are not properly transferred due to permissions errors. Presumably running the operation as root would take care of that but if you do that remember to change $HOME to the actual path to your home directory, otherwise it will backup /root/. Personally I'm not bothered running it as root in cron because it looks as though what is not properly transferred is insignificant.

It's a simple script, but if anyone has any comments or suggestions I'd like to hear them as I'm a bit of a noob when it comes to scripting.

Send text messages from the command line. A simple bash script which relies on http://cabbagetexter.com, an excellent service maintained by boardsie Sam Vimes. It's a bit crude, no input validation and lacks polish but it gets the job done. I was going to write it in Python but Python cannot work through the TCD authenticated proxy, while wget can.

#!/bin/bash

conf_dir="$HOME/.msg"
if [[ ! -d $conf_dir ]]; then
    mkdir $conf_dir
fi
num_file="$conf_dir/numbers"
login_file="$conf_dir/login"
login=$(cat $login_file)
unum=$(echo $login | awk -F ',' '{print $1}')
pin=$(echo $login | awk -F ',' '{print $2}')
serv=$(echo $login | awk -F ',' '{print $3}')

function add_number {
    name=$1
    num=$2
    echo "$1,$2" >> $num_file
    echo "Number added."
}

function send_msg {
    numtest='^[[:digit:]]+$'
    if [[ "$1" =~ $numtest ]]; then
        num=$1
    else
        num=$(cat $num_file | grep "$1" | awk -F ',' '{print $2}')
    fi
    shift
    msg=$(echo "$@" | sed 's/\ /%20/g' | sed "s/'/%27/g")
    url="http://cabbagetexter.com/send.php?u=$unum&p=$pin&s=$serv&d=$num&m=$msg"
    ans=$(wget -qO - $url)
    case $ans in
        -1  )   echo "Invalid login. Message not sent." ;;
        -2  )   echo "Could not log in to network website. Message not sent." ;;
        -5  )   echo "Problem with network website. Message not sent." ;;
        ""  )   echo "No message specified. Message not sent." ;;
        *   )   echo "Message sent. $ans messages left."
    esac
}

function set_login {
    echo "$1,$2,$3" > $login_file
    echo "Login set."
}

function empty {
    echo "" > $num_file
    echo "Contact book cleared."
}

function view_contacts {
    cat $num_file
}

function gui {
    if [[ $(which zenity 2>/dev/null) ]]; then
        send_msg $(zenity --entry --text='Enter the number or name of the recipient folowed by your message.')
    fi
}

case "$1" in
    "add"       )   add_number "$2" "$3" ;;
    "login"     )   set_login "$2" "$3" "$4" ;;
    "clear"     )   empty ;;
    "contacts"  )   view_contacts ;;
    ""          )   gui ;;
    *           )   send_msg "$@"
esac    

Usage is as follows (presuming the script is saved as msg):

On the first use, set your login details by typing:

msg login <number> <pin> <m, v or o>

Add a contact (a simple name-number association) with:

msg add <name> <number>

To send a message, type:

msg <name or number> <message>

View your saved contacts with:

msg contacts

Clear contacts with:

msg clear

Running the script with no arguments, if you have zenity installed, opens a simple GUI prompt. Enter <name or number> <message> to send a message.

If you see something wrong with it, please let me know. Thanks.

Sometimes my internet randomly goes down for five minutes, an hour or a few hours. I just wrote up this simple thing to continuously check for internet connectivity by attempting typing Google, and alert you (and exit) when it manages to connect. It currently waits 10 seconds between ping attempts, just change the 10 to something else to vary sleeping time. Run it, fork it to background and go about your offline work, and don't worry about checking to see if you're back online every 5 minutes.

#!/bin/sh

on_success() {
        zenity --info --text="Internet is working."
        exit 0 
}

while true; do ping -c 1 google.com > /dev/null 2>&1 && on_success || sleep 10; done