copying files in terminal and keep older versions

StepNjump · 01-08-2017, 05:47 PM

Recently, I just learned how to write simple shell scripts. One of them simply duplicate certain files on my system that happen to be crucial to me for backup purposes.

cp /dir/dir/file1 /samedir/samedir/file1.bak
My scripts gets executed every time I sign on the system. However it always overwrites file1.bak, which is not intended nor wanted. I would like to find a way to keep all created files separated. Maybe something like file1(1).bak, file1(2).bak or something of the like. Strangely enough, that works great when copying and pasting in X, but not by using the cp command.

VMS was great for certain things, namely that every time we would write to a file called file.bak, it would keep all previous versions by adding a tailing ':' followed by the version number of that file at the end of the file ie: file.bak:1, file.bak:2, file.bak:521, etc...

We used to get rid of previous versions with the purge command purge file.bak

Any suggestions ?

Thanks,

StepNjump

BW-userx · 01-08-2017, 06:08 PM

man cp

Code:

       --backup[=CONTROL]
              make a backup of each existing destination file

       -b     like --backup but does not accept an argument

pseudo code

Code:

if [[ -f filename.bak ]] ; then 
cp source destanation/filename(1).bak
fi

but it is a little more complicated if you already have a filename(1).bak ...
http://www.tldp.org/LDP/abs/html/fto.html

you could use this. Just modify it to your needs:

This function searches the directory and finds where I left off at. returning that highest number to a file I added a numbering system like you're talking of. filename(1).bak filename(2).bak etc

Code:

#!/bin/bash

countnum="$(find /home/userx/testscript/lost -name "*.mp3" | wc -l )"

FILES="$(cd /home/userx/testscript/lost/ && ls *.mp3)"

MAXNUM="$(find ~/testscript/lost -type f -name "*.mp3" | wc -l )"
typeset -i i
i=0

 function getLastNum()
 {
for file in $FILES 
do

echo $file
      # nstring=${file##*/} #gets just the file name
      
       lstring=${file##*"("} #chops off Lside to the ( leaving num )
       rstring=${lstring%%")"*} #chops off Rside to the ) leaving the num
  
       arr[$i]=$rstring
       (( i++ ))
  done  


 for (( a=0; a <  $countnum ; a++ )) ; do

       if (( arr[a+1] < arr[a] )); then
                store=arr[$a]
		arr[$a]=arr[$a+1]
		arr[$a+1]=$store
                BigNum=$store
       fi
done



return $BigNum

}
getLastNum

as such

Code:

userx@voider~:>> nstring="noere(1)"
userx@voider~:>> lstring=${nstring##*"("}
userx@voider~:>> echo $lstring
1)

userx@voider~:>> rstring=${lstring%%")"*} 
userx@voider~:>> echo $rstring
1

now you will know where you left off at.

Code:

lastNum="$(( $BigNum+1 ))"

gives you the next number to use.

another snippet of my script to give you an idea on how to get the just the file name then add the number to the next file. using basename and dirname too can be used instead if you like.

Code:

 c=$FILENAME
 
 xpath=${c%/*} 
 
 xbase=${c##*/}
 xfext=${xbase##*.}
 xpref=${xbase%.*}
 path=${xpath}
  pref=${xpref}
 ext=${xfext}
 

newFile="$pref-(Lost-Song-Number-("$lastNum")).mp3"

Manipulating Strings

Bash String Manipulation Examples – Length, Substring, Find and Replace

Jjanel · 01-09-2017, 06:48 AM

Yea VMS! Append date? Append :#++ Idk

cpv x -> x:1 then x:2 then x:3 ...
man cpv: ToBeWritten by LQscriptGuru. Works like VMS, incr :<ver#> if dest exists.

Habitual · 01-09-2017, 07:07 AM

Seems like you need a solid

Code:

cp /dir/{file1,file1.bak}

pre-flight:

Code:

echo cp /dir/{file1,file1.bak}

ondoho · 01-09-2017, 02:28 PM

how about

Code:

cp file file.$(date +%s).bak

?

and:

Code:

man date

(funny, that reads like mandate).