system (<command>, $retval)

The following example shows the printing of a content including a variable coming from the PHP script:

system('echo "'.$message.'"|lpr -o page-left=35 ', $retval );

This looks like a very good intro tutorial: http://www.makeuseof.com/tag/learn-automate-mac-applescript-part-1-introduction/

Kudos to MakeUseOf!

Question: I have a .ISO file representing the image of a DVD and I want to know the LABEL of that DVD.

Answer: Issue the command

dd if=/<path>/filename.iso bs=1 skip=32808 count=32

on whatever Linux terminal.

For example, here’s what is returned for a backup copy of DVD I legally own:

Input command:
dd if=Natale\ in\ Casa\ Muppets.iso bs=1 skip=32808 count=32

Output:
MUPPETS_CHRISTMAS_CAROL         32+0 records in
32+0 records out
32 bytes (32 B) copied, 0.00129793 s, 24.7 kB/s

Enjoy!

Give a look to the script below, which I’m writing here for future reference.

#!/bin/bash
#
# This script creates a list of file or symbolic link to pictures in a directory
# The pictures are dynamically selected within a library of thousands
# This is to allow a wireless frame to display daily an ever changing list
# of pictures

# Define variable to be the target directory where we put the link/pictures
# This directory is regularly scanned by MediaTomb, the uPnP server talking to
# the digital frame

# Define variable to be the root directory where it will start to scan
scandir=/media/allphotos

# Clean previous contents of the directory used for streaming
cd /var/streampix
rm -rf *

# Define cycle to set the max number of photos to be displayed
# (like from 1 to 50 repeat)
for i in `seq 1 50`

# list the dir, pick a random file, add to the list
do
y="$(find $scandir -type f -iregex ‘.*\.\(bmp\|gif\|jpg\|png\)$’ | sort -R | head -1)"
cp "$y" /var/streampix/
done

Enjoy!

I’ll try to comment them, so that readers will be able to readapt them to their needs.

Need: I have a list of files in subdirectories under main one and I want to copy only some of them to new location. I have the list of files I need in a text file.

#!/bin/bash
#
DIR=root # Location where the list I want to extract is located
FILE=wantedlist # with the name of the file
DIR_VIDEO=”/media/bigdisk” # Master repository containing iles in subdirectories
COPY_DEST=”/media/externalHDD/backup” # where I want to put my files
y=`cat /$DIR/$FILE|wc -l` # counting how many files I want to copy
for i in `seq 1 $y` # starting the cycle
do
# I’ll copy file mentioned in every line in the text list in new location
cp -R /$DIR_VIDEO/”`cat /$DIR/$FILE | tail -$i|head -1`” $COPY_DEST
done

Please note the usage of head and tail to go line by line in reverse order , while the cycle allows me to repeat this for each line in the text list.

I have multiple files with extension .sh.modified and I need to rename them all into .sh extension.

Solution:

for file in *.sh.modified; do mv ${file} ${file%sh.modified}.sh; done

#!/bin/bash
#
# Script to check a directory and write in file the new files
# since last check.
#
# Written by RoarinPenguin (roarinpenguin@rottigni.net) on
# 21 march 2009
# Released under GPL License
#
# You need to create a file called lastcheck.time in same
# directory of this script
#

ADMIN="change to administrator email address"
DIR2MON=/var/www/dir-clienti

> ./newfiles.list
echo "Last check for new files, done on "`date` >> ./newfiles.list
find $DIR2MON -maxdepth 5 -newer ./lastcheck.time >> ./newfiles.list
touch ./lastcheck.time

But sometimes sed does perfectly fantastic job, like it did for me few minutes ago… with some caveats.

My goal was to replace $i with the value of the variable, determined by the first part of the script:

for i in `seq 1 50`;

the problem was that I made rest of the cycle as follows:

do cat newtest.xml|sed –e ‘s/variable/$i/’ >> multifirewallimport.xml; done

and the result was that through all my file the word variable was replaced with the word $i.

What was wrong? Well… Googling for it I discovered the issue was in usage of single quote instead of double quote.

The correct form is:

for i in `seq 1 50`; do cat newtest.xml|sed -e "s/variable/$i/" >> multifirewallimport.xml; done

for i in `cat filename`
do
echo $i
done

does not work since it will consider every word as a single variable.

This second script does the job:

IFS=\$    ==> this sets the line separator as EOL
while read i    ==> this read variables separated by EOL and stores value in $i
do
echo $i    ==> this echoes the value of $i. Replace echo command with whatever you want to do with filenames
done < file-containing-the-list    ==> this ends the while do cycle and takes input from file where filenames are stored