URL Decode in C ( http query string )

/*

* to decode http query_string ie to convert special characters in
* Query String to their original form like %20 to space %22 to  
* double-quote
*
* if 'str' contains  type=it%20is%20simple%20%22text%22
* ie when called as
* http://localhost/cgi-bin/a.out?type=it is simple "text"
* 
* when used as cgi-bin with apache
* 
* NOTE:
* for GET method there is environment variable set by apache QUERY_STRING
* for POST method, need to read from STDIN 
*
*/ 

int urlDecode(char *str);

int main(int argc, char *argv[])
{
    char *query_string;
    printf("Content-type: text/html\r\n\r\n"); /* required */
    query_string = getenv("QUERY_STRING");
    if (!query_string)
    {
        printf("QUERY_STRING not found\n"); return 1;
    }
    urlDecode(query_string);
    printf("text received: %s \n", query_string);
}

int urlDecode(char *str)
{
    unsigned int i;
    char tmp[BUFSIZ];
    char *ptr = tmp;
    memset(tmp, 0, sizeof(tmp));

    for (i=0; i < strlen(str); i++)
    {
        if (str[i] != '%')
        {
            *ptr++ = str[i];
            continue;
        }

        if (!isdigit(str[i+1]) || !isdigit(str[i+2]))
        {
            *ptr++ = str[i];
            continue;
        }

        *ptr++ = ((str[i+1] - '0') << 4) | (str[i+2] - '0');
        i += 2;
    }
    *ptr = '\0';
    strcpy(str, tmp);
    return 0;
}

satellite.sh - sync favorite folders using pen-drive

#!/bin/bash
# save it as '~/bin/satellite.sh'

ZIP_DRIVE_NAME="KING1GB"

INVALID="usage: $0  < upload | download >"
UP="UPLOAD"
DOWN="DOWNLOAD"

if [ $# -ne 1 ];then
    echo "$INVALID"
    exit 1
fi

arg=$1
a_string=""
a_string_common="Press Enter to continue or Ctrl+C to exit: "
text=""

case "$arg" in
upload|\>)
    arg=$UP
    a_string="UPLOADING\nwill overwrite SATELLITE \033[35G"${a_string_common}
    ;;
download|\<)
    arg=$DOWN
    a_string="DOWNLOADING\nwill overwrite BASE \033[35G"${a_string_common}
    ;;
*)
    arg=NONE
    echo "$INVALID"
    exit 1
esac

echo -ne "${a_string}"
read text

# ---- BLOCK-START ----
# add path to both arrays
# and basename of the path must be a folder
# 
SATPATH=/media/${ZIP_DRIVE_NAME}/.A-BOX
if [ ! -d ${SATPATH} ];then
    SATPATH=/media/${USER}/${ZIP_DRIVE_NAME}/.A-BOX
    if [ ! -d ${SATPATH} ];then
        echo "remote path '$SATPATH' does not exit, check usb"
        exit 2
    fi
fi
 
path_satellite[1]="$SATPATH/bin"
path_satellite[2]="$SATPATH/learning"
path_satellite[3]="$SATPATH/scripting"
path_satellite[4]="$SATPATH/Wallpapers"
#
path_base[1]="$HOME/bin"
path_base[2]="$HOME/Documents/learning"
path_base[3]="$HOME/Documents/turbo/scripting"path_base[4]="$HOME/Pictures/Wallpapers"
#
# ---- BLOCK-END ----

#
# check that both arrays contains same number of elements
#
if [ ${#path_satellite[@]} -ne ${#path_base[@]} ];then
    echo -e "mismatch detected in ${0}\nkindly verify both arrays, exiting"
    exit 1
fi

total=${#path_base[@]}
echo "total: $total"

#
# check that order of elements in both arrays are same
#
counter=1
while [ $counter -le $total ]
do
    temp_sate=$(basename ${path_satellite[$counter]})
    temp_base=$(basename ${path_base[$counter]})

    if [ "${temp_sate}" != "${temp_base}" ];then
        echo "satellite: ${temp_sate}"
        echo "base     : ${temp_base}"
        echo "above paths does not match in ${0}, kindly check and rerun"
        exit 1
    fi
    counter=$(expr $counter + 1)
done

#
# chech if local copy of satellite.sh is latest
#
f_remote="$SATPATH/bin/satellite.sh"
f_local="$HOME/bin/satellite.sh"

if [ -f "${f_remote}" ];then

    skip_check="no"

    script_remote=$(stat ${f_remote} | grep "Modify")
    script_remote=$(echo ${script_remote:8:19} | sed 's/[- :]//g')

    script_local=$(stat ${f_local} | grep "Modify")
    script_local=$(echo ${script_local:8:19} | sed 's/[- :]//g')

    cur_timestamp=$(date +"%Y%m%d%H%M%S")

    echo "remote: ${script_remote}"
    echo "local : ${script_local}"

    #
    # got this error when run 'satellite.sh upload' on ubuntu 12.04
    # followed by running 'satellite.sh download' on fedora 16
    # on fedora 16 timestamp of /media/SATELLITE/.A-BOX/satellite.sh was cur+05:30
    #
    if [ "${script_remote}" -gt "${cur_timestamp}" ];then
        echo "remote script timestamp is set to future !!! could be time-setting problem !!!"
        echo -n "do you want to SKIP timestamp check !!! : "
        read choice

        if [ "$choice" = "y" -o "$choice" = "Y" ];then
            echo "skipping timestamp check"
            skip_check="yes"
        fi
    fi

    if [ "${script_remote}" -gt "${script_local}" -a "$skip_check" = "no" ];then
        cp -f ${f_remote} ${f_local}
        echo "local copy was outdated, hence updated"
        echo "re-run: ${0}"
        exit 1
    fi
fi


RSYNC_CMD="-av --delete --exclude=.metadata"

if [ "$arg" = "UPLOAD" ];then
    for (( x=1; x<=$total; x++))
    do
        [ ! -d ${path_satellite[x]} ] && mkdir -p ${path_satellite[x]}
        echo -e "\033[37;42;1m==> syncing\033[35G`basename ${path_base[x]}/`\033[m"
        #rsync -av --delete --exclude=".metadata" ${path_base[x]}/ ${path_satellite[x]}
        rsync ${RSYNC_CMD} ${path_base[x]}/ ${path_satellite[x]}
    done

elif [ "$arg" = "DOWNLOAD" ];then
    for (( x=1; x<=$total; x++))
    do
        [ ! -d ${path_base[x]} ] && mkdir -p ${path_base[x]}
        echo -e "\033[37;42;1m==> syncing\033[35G`basename ${path_satellite[x]}`\033[m"
        #rsync -av --delete --exclude=".metadata" ${path_satellite[x]}/ ${path_base[x]}
        rsync ${RSYNC_CMD} ${path_satellite[x]}/ ${path_base[x]}

    done

else
    echo "invalid option"
    exit 1
fi

echo -e "\033[;44;1m==> syncing\033[35GDONE\033[m"



#------------ END ------------



SATELLITE is the name of my pen-drive
run './satellite.sh upload' or './satellite.sh \>' to sync data to pen-drive
and './satellite.sh download' or './satellite.sh \<' to sync data on machine from pen-drive

it helps in syncing data, if work on different machines/laptops and need to carry personal/required folders with you all time.

before starting work use 'download' after finishing work 'upload' to SATELLITE.

time delay routine in C

/*
 * filename : counter.c
 * date     : 09-12-2011
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

char default_msg[] = "counter will expire in following seconds";

int main(int argc, char* argv[])
{
    char *msg = default_msg;
    int delay = 0, hour, min, sec, days;
    int i;

    days = hour = min = sec = 0;

    switch (argc)
    {
        case 3:
            msg = argv[2];
        case 2:
            for (i=0; i < strlen(argv[1]); i++)
            {
                if (!isdigit(argv[1][i]))
                {
                    printf("invalid digit '%c' at position %d in argument\n", argv[1][i], i);
                    return -1;
                }
            }
            delay = atoi(argv[1]);
            break;
        default:
            printf("invalid number of arguments\n"
                    "usage: %s [\"message\"]\n", argv[0]);
            fflush(stdout);
            return -1;
    }

    /*
     * calculate exact time in hh:mm:ss entered for delay-sec
     */
    sec  = delay % 60;
    min  = (delay / 60) % 60;
    hour = (delay / 3600) % 24;
    days = delay / (3600 * 24);

    printf("MSG: %s - DAYS: %d, %d:%d:%d\n", msg, days, hour, min, sec);
    for (i=delay; i >= 0 ; i--)
    {
        printf("\rcounter: %d", i);
        fflush(stdout);        sleep(1);
    }
    printf("\n");

    return 0;
}

/*

* compile with gcc

* gcc counter.c -o COUNTER

* ./COUNTER 15

* ./COUNTER 97405

*/

Backup utility in Bash Shell Script

save following bash shell script as mybackup.sh
#!/bin/bash
#
# Filename: mybackup.sh
# Author : Simrat Pal Singh
# Email : simrat.khokhar@gmail.com
#
# Modified: 02-03-2011
# to even work with paths having space
#

if [ $# -ne 2 ];then
echo "Wrong number of arguments"
echo "Usage: $0 /path/to/source /path/destination/"
exit 1
fi

input=$1
backupdate=$(date +%d%m%Y)
foldername=$(basename "$1")
inputpath=$(dirname "$1")
outpath="${2}"
output="${2}${foldername}_${backupdate}"

case ${foldername} in
*.tar.bz2)
[ "${inputpath}" = "" ] && inputpath="."i
bzip2 -dck "${inputpath}"/"${foldername}" | tar -C "${outpath}" -x
;;

*)
counter=0
while [ -f "${output}.${counter}.tar.bz2" ]
do
counter=$(expr $counter + 1)
done

output="${output}.${counter}"

# run tar and bzip2 command to make backup
tar -C "${inputpath}" -c "$foldername"|bzip2 -cz >"${output}.tar.bz2"
chmod -x "${output}.tar.bz2"
;;
esac

#--------------------- END ------------------------


execute with two arguments as:
sh mybackup.sh /path/source /path/destination/

it will create 'source_ddmmyyyy.x.tar.bz2' at /path/destination/
where 'x' is integer value, ie if you run it twice on same day for same source folder, it will automatically incremented.

if source folder is .tar.bz2, then it will unzip the contents at the destination path