Puppy Linux Discussion Forum Forum Index Puppy Linux Discussion Forum
Puppy HOME page : puppylinux.com
"THE" alternative forum : puppylinux.info
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

The time now is Sun 26 May 2013, 00:43
All times are UTC - 4

 Forum index » Off-Topic Area » Programming
Problems with sed in script
Post new topic   Reply to topic View previous topic :: View next topic
Page 1 of 1 [7 Posts]  
Author Message
2lss

Joined: 20 Sep 2009
Posts: 225
PostPosted: Sat 08 May 2010, 20:07    Post subject:  Problems with sed in script  
I'm working on a little script to synchronize music between my mp3 player, external hdd and my music library on my computer. So far I've got:
Code:
MUSICDIR=/root/Music

DEVDIR=/mnt/sdb1/music

diff $MUSICDIR $DEVDIR | grep "Only in $MUSICDIR" | sed -e s/"Only in $MUSICDIR: "//


the diff piped into the grep command gives something like:
Code:
Only in root/Music: Alice in Chains
Only in root/Music: Foo Fighters
etc.


so I want to strip the "Only in root/Music: " part using sed but I'm running into problems. If I try what I have above I get:
Code:
sed: -e expression #1, char 17: unknown option to `s'


The man page for sed says:
Code:
s/regexp/replacement/
              Attempt  to  match  regexp  against the pattern space.  If successful, replace that portion matched with replacement.  The replacement may
              contain the special character & to refer to that portion of the pattern space which matched, and the special  escapes  \1  through  \9  to
              refer to the corresponding matching sub-expressions in the regexp.


From what I can tell, sed is getting screwed up b/c the string MUSICDIR contains slashes but I'm not sure how to correct it. I tried just about every combination of sed I can find along with different styles of quoting but I still get the same error. Anyone have any ideas?
Back to top
View user's profile Send private message 
big_bass


Joined: 13 Aug 2007
Posts: 1736
PostPosted: Sat 08 May 2010, 22:27    Post subject:  
Hey 2lss


Quote:
so I want to strip the "Only in root/Music: " part using sed


Code:
echo "Only in root/Music: Alice in Chains" | sed -e 's/Only in root\/Music://g'



so you could test it with echo first

Code:
| sed -e 's/Only in root\/Music://g'


Joe
_________________
slackware 14
Back to top
View user's profile Send private message 
potong

Joined: 06 Mar 2009
Posts: 88
PostPosted: Sun 09 May 2010, 01:13    Post subject:  
2lss:

The problem your having is not so much with sed but with quoting in the shell.

As a rule of thumb it's always a good idea to single quote any commands to sed on the command line.

In this case you want to interpolate a variable within the sed command; so just single quote around the bash variable like so:
Code:
# a=/tmp/a b=/tmp/b; rm -rf $a $b; mkdir $a $b
# for x in {a..f};do touch $a/$x;done                #afterthought: same as
# for x in {d..h};do touch $b/$x;done               # touch $a/{a..f} $b/{d..h}
# diff $a $b|sed -n 's|Only in '$a': ||p'
a
b
c
#

The sed command could do with a little explanation
Code:
sed -n 's|Only in '$a': ||p'

    sed -n means turn off automatic printed output to stdout. In effect this means nothing gets printed unless you choose to print it out.

    's|Only in ' first half of sed substitute command using "|" as a delimiter.

    $a is the bash variable containing the directory name (has "/"'s in it hence the "|" delimiters)

    ': ||p' second half of substitute command which in effect wipes "Only in /tmp/a: " from input line. The p prints out to stdout whats in the pattern space if the substitute command matched.

Generally speaking you never need grep followed by sed as sed can do it all (less overhead and quicker)

Here's a link to a good sed tutorial

HTH

Potong
Back to top
View user's profile Send private message 
2lss

Joined: 20 Sep 2009
Posts: 225
PostPosted: Mon 10 May 2010, 15:35    Post subject:  
big_bass:Thanks for your suggestion. I tried and it works but since I'm planning on using multiple instances of sed and using the script on different machines with different music directories I would rather change the MUSICDIR variable at the beginning than change every instance of sed in the script.

potong: I modified the script to:
Code:
MUSICDIR=/root/Music

DEVDIR=/mnt/sdb1/music

diff $MUSICDIR $DEVDIR | sed -n 's|Only in '$MUSICDIR': ||p'


Everything seems to be working good, thanks
Back to top
View user's profile Send private message 
jemimah


Joined: 26 Aug 2009
Posts: 4309
Location: Tampa, FL
PostPosted: Mon 10 May 2010, 17:20    Post subject:  
Why not use rsync?

Puppy has the GAdmin Rsync frontend included; it's pretty nice.
Back to top
View user's profile Send private message Visit poster's website 
big_bass


Joined: 13 Aug 2007
Posts: 1736
PostPosted: Mon 10 May 2010, 22:34    Post subject:  
2lss
Quote:
big_bass:Thanks for your suggestion. I tried and it works but since I'm planning on using multiple instances of sed and using the script on different machines with different music directories I would rather change the MUSICDIR variable at the beginning than change every instance of sed in the script.


Hey 2lss
Hey potong
Hey jemimah


good to hear that the final code that potong pasted was useful
so that you could modify it to you needs

I didn't read in to what you were doing just answered the question with sed


I know that potong likes using gtkdialog so here's a code example using Xdialog that could be converted hint ,hint (gtkdialog apps are more flexible )

its a drag N drop so now it doesnt matter what folders you select

I guess that you want some sort of list generated ??





in this code snippet I dont use sed I used cut

after looking at the out put with diff
Code:
| cut  -f 2 -d :


seemed easier

how to use :
1.)make it executable
2.)click on it once to launch it
3.)drag N drop your database folder in FIRST the input box
4.)drag N drop your possible new files folder in the SECOND input box



updated 5-11-2010 I added a viewer I didnt like the editor opening at such a large size the editor works well with patches but not with this
Code:

#!/bin/sh


# just a simple diff tool for the lazy
# there are better but this is easy :D
# Joe Arose
# call this dnd_database_diff
#
# **modifed from my dnd_diff for making patches
# added a viewer
# the data base folder is your grownig database
# the  new folder directory may have new files not in the data base
# if any new files are found they are listed in a txt file for you

DIALOG=Xdialog

$DIALOG --title "The data base directory    " \
        --inputbox "Type in a value or Drag N drop.
         the data base directory folder
         \n
" 0 0  2> /tmp/one.txt

retval=$?



input=`cat /tmp/one.txt`


case $retval in
  0)
    echo "Input string is '$input'";;
  1)
    echo "Cancel pressed."
    exit;;
  255)
    echo "Box closed."
    exit;;
esac

#----------------------------------
$DIALOG --title "The possible new files   " \
        --inputbox "Type in a value or Drag N drop.
        the new folder directory this may have some new files
        the name will be given from this folder .txt
        and placed in root\n
" 0 0 2>/tmp/two.txt

retval=$?

input2=`cat /tmp/two.txt`

case $retval in
  0)
    echo "Input string is '$input2'";;
  1)
    echo "Cancel pressed."
    exit;;
  255)
    echo "Box closed."
    exit;;
esac

diff  $input $input2 | grep "$input2" | cut  -f 2 -d : >/root/`basename $input2`.txt

#or you could do this if you have another editor installed
#$DEFAULTTEXTEDITOR  /root/`basename $input2`.txt
DIFF_LIST=/root/`basename $input2`.txt
 
echo "`cat $DIFF_LIST`" | Xdialog --title " differences" \--backtitle "differences             "     \--textbox "-" 0 0


 
rm -f /tmp/two.txt
rm -f /tmp/one.txt









Joe
_________________
slackware 14
Back to top
View user's profile Send private message 
2lss

Joined: 20 Sep 2009
Posts: 225
PostPosted: Wed 12 May 2010, 01:47    Post subject:  
jemimah: I have been looking at rsync and may include it somewhere else in the script. I don't know the ins and outs of it yet, hopefully I can find some tutorials on how to use it. I also didn't know about GAdmin Rsync, thanks for the tip.

big_bass: I like your script, I will incorporate it into my music sync script. The only bad part is the drag and drop only works with rox and not pcman.

I had to modify it slightly to get it to work. The three lines with Xdialog I had to change to this format without the \ :
Code:
$DIALOG --title "The data base directory    " --inputbox "Type in a value or Drag N drop the data base directory folder\n" 0 0 2> /tmp/one.txt




The reason I am writing this script is b/c I have a very obsessive compulsive way I organize my music. I've tried many different music players and syncing tools but none work the way I want. With 2 computers, an ipod running rockbox, and an external backup hdd, organizing my music is taking way to long. What I have posted so far is just the tip of the iceberg. It's probably not the most efficient method but it will get me started.
Back to top
View user's profile Send private message 
Display posts from previous:   Sort by:   
Page 1 of 1 [7 Posts]  
Post new topic   Reply to topic View previous topic :: View next topic
 Forum index » Off-Topic Area » Programming
Jump to:  


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Powered by phpBB © 2001, 2005 phpBB Group

[ Time: 0.0767s ][ Queries: 12 (0.0170s) ][ GZIP on ]