Found a great post over at good coders code, great reuse. This one deals with performing operations on sets using only unix (bash) command line operations on files of text.

* Set Membership. Test if an element belongs to a set.
* Set Equality. Test if two sets contain the same elements.
* Set Cardinality. Return the number of elements in the set.
* Subset Test. Test if a given set is a subset of another set.
* Set Union. Find union of two sets.
* Set Intersection. Find intersection of two sets.
* Set Complement. Given two sets A and B, find all elements in A that are not in B.
* Set Symmetric Difference. Find symmetric difference of two sets.
* Power Set. Generate all subsets of a set.
* Set Cartesian Product. Find A x B.
* Disjoint Set Test. Test if two sets are disjoint.
* Empty Set Test. Test if a given set is empty.
* Minimum. Find the smallest element of a set.
* Maximum. Find the largest element of a set.

It deals with such commands as sed, awk, tr, sort, comm, grep and wc. This is a good post for anyone dealing with data via command line linux.

Full article here.

I created this Bash script as a project for the system administration course I’m taking for the summer. I’m sure there are bugs in it, so let me know if you find any.

It basically uses an XML configuration file, which includes the source, destination, and any excludes from the transfer. You then pass either -u or -d (upload or download) and the options -x (delete if not in source) and -f (force). Destination can be local or remote, but source must be local.

Here is the code:

#!/bin/bash
## Transfer Script
## By David Drager
## CSC586: Summer II 2008
## Requires: xml2, rsync

## Settings
tempdir="/tmp/"
rsynccommand="/usr/bin/rsync"

## Usage command
usage="usage: transfer.sh [options] <config-file>.xmlnoptions:n  -d or -u:t download or upload, resp. one and only one must be presentn  -f:ttforce transfer regardless of 'newness' of filen  -x:ttdelete items in target not present in source"

# Check to make sure temporary directory exists
[ -d $tempdir ] || { echo -e "Error: Could not locate a temporary directory. See file settings."; exit 1; }

# Usage Command
[ $# -eq 0 ] && { echo -e "ERROR: Needs at least the -d or -u flag plus a config file.nn$usage"; exit 1; }

## Get options passed to the program
while getopts "dufx" flag
do
  [ "$flag" = "?" ] && echo -e "ERROR: Flag(s) not valid.nn$usage" && exit 1;
  eval "opt_$flag=1"
done
shift $((OPTIND-1))
configfile="$1"

if [ "$opt_d" = 1 ] && [ "$opt_u" = 1 ]
then
  echo -e "Error: Use either -u Upload or -d Download, but not bothn$usage"; exit 1;
elif  [ "$opt_u" = "" ] && [ "$opt_d" = "" ]
then
    echo -e "Error: Use either -u Upload or -d Download, but not bothn$usage"; exit 1;
fi

if [ "$opt_f" = 1 ]; then
  force=1
fi

if [ "$opt_x" = 1 ]; then
  deltar=1
fi

## Make sure config file is located
if [ "$configfile" != "" ]
then
  [ -f "$configfile" ] || { echo -e "Error: Config file not found.n$usage"; exit 1; }
else
   echo -e "Error: Config file not specified.n$usage"; exit 1;
fi

## End of swich verification

# echo Action: "$action"
# echo Force: "$force"
# echo Delete Target Files: "$deltar"
# echo Config: "$configfile"

## Now read config file

## Set temp file for XML parsing
tempfile="$tempdir"transferscript_$$
tempexcludes="$tempdir"transferscriptexcludes_$$
# echo -e "Temp:$tempfile"

# Run config file through xml2
xml2 < "$configfile" > "$tempfile"

[ -f "$tempfile" ] || { echo -e "There was a problem processing the XML file."; exit 1; }

# Make sure that source and destination are found
excludelist=""
while read line; do
    key=$(echo $line | awk -F '=' '{print $1}')
    value=$(echo $line | awk -F '=' '{print $2}')
    if [ "$key" = "/sync/@src" ]; then
      source="$value";
    elif [ "$key" = "/sync/@dst" ]; then
      destination="$value"
      # Add any exclude options to array
    elif [ "$key" = "/sync/exclude" ]; then
      tempexcl=("$value")
      excludelist=("${excludelist[@]}" "${tempexcl[@]}")
    fi
done < "$tempfile"

[ "$source" ] || { echo "Error: Config file must include a source"; exit 1; }
[ "$destination" ] || { echo "Error: Config file must include a destination"; exit 1; }

source="$source/"
destination="$destination/"

[ -d "$source" ] || { echo "Error: Source must be a local directory"; exit 1; }

excludes=""
excludes=${excludelist[@]}

# echo Excludes: "(${#excludelist[@]}): $excludes"

## Clean up temp file from xml process
rm "$tempfile"

## Build up the command line

[ -f "$rsynccommand" ] || { echo -e "Error: Could not locate rsync command."; exit 1; }

fullcommand="$rsynccommand"
fulltestcommand="$rsynccommand"

if [ "$opt_f" == "1" ]
then
    fulltestcommand="$fulltestcommand -nva"
    fullcommand="$fullcommand -a"
else
    fulltestcommand="$fulltestcommand -nvau"
    fullcommand="$fullcommand -au"
fi

if [ "$opt_u" == "1" ]
then
  fileorder="$source $destination"
  echo "Evaluating transfer from $source ==> $destination"
elif [ "$opt_d" == "1" ]
then
  fileorder="$destination $source"
  echo "Evaluating transfer from $destination ==> $source"
fi

[ "$opt_x" == "1" ] && { fulltestcommand="$fulltestcommand --delete"; fullcommand="$fullcommand --delete"; }

## Move exclude list to a file.
## This duplicates as above but I originally thought we were passing it to rsync as a list and not as a file.

[ "${#excludelist[@]}" -gt 0 ] && {
    tempfile="$tempdir"transferscript_$$
    touch "$tempfile"
    echo "$excludes" | tr " " "n" > "$tempfile"
    fulltestcommand="$fulltestcommand"" --exclude-from=$tempfile"
    fullcommand="$fullcommand"" --exclude-from=$tempfile"
}

fulltestcommand="$fulltestcommand $fileorder"
fullcommand="$fullcommand $fileorder"

# We only want lines minus top line and bottom 3 lines
testresult=`$fulltestcommand | tail --lines=+2 | head --lines=-3`

# If this is empty, then notify that no files would be transferred.
 [ "$testresult" ] || { echo "This command would not transfer any files. Script exiting."; rm "$tempfile"; exit 1; }

# Display changes
echo -e "Changes to be made:n--------------------n$testresultn--------------------"

# Check to see if we really want to run the command.
echo "Do you wish to perform this command? $fullcommand (y/n)[y]"
read confirm
if [ "$confirm" = "y" ] || [ "$confirm" = "" ]
then
    echo "Performing transfer..."
    # Without -v this will not output anything.
    $fullcommand
    echo "Transfer complete."
    rm "$tempfile"
else
    echo "Cancelling transfer..."
    rm "$tempfile"
fi

exit 0

Here is the sample config file:

<sync src="/home/dir/bash-prog/dir1/" dst="login@some.machine:/home/dir/dir2">
        <exclude>
          .test3
          another.*
        </exclude>
</sync>

Wow - I get so frustrated when I try to copy some files over old ones and I get:

[root@server1 wordpress]# cp -Rf * ../public_html/
cp: overwrite `../public_html/license.txt'? y

-R is recursive, but -f is supposed to copy over without confirmation. What could it be?!

Check out your alias command using ‘alias’:

[root@server1 wordpress]# alias
alias cp='cp -i'

Sure enough - alias is set on Redhat Based systems into -i, or interactive mode. Remove this alias with ‘unalias cp’ and it will be removed.

Happy copying!

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