These two commands tell you which package owns a particular file for an RPM or DEB based system respectively.

rpmquery –whatprovides <path-to-file>

dpkg-query –search <path-to-file>

(The short form for dpkg is -S)

To list the files owned by a package use:

rpmquery –list <package>

dpkg-query -L <package>

(This long form for debian is –listfiles )

A useful utility to find all the other files in a package for a given binary (in this case lsof) is:

rpmquery –list $(rpmquery –whatprovides $(which lsof ) )

Or

dpkg-query -L $(dpkg-query –search $( which lsof ) | sed ‘s!\:.*!!’ )

rpms are saved in a file format called cpio, with a few minor changes.  To convert an rpm to this format use rpm2cpio.  The cpio binary is responsible for manipulating these files.  So if you want to treat that rpm as just another archive, and extract the files in it, you can link a couple of tools.  Here’s the line:

rpm2cpio your.rpm | cpio -di

A small project I have in the embedded side of things requires keeping track of information per index, what one would normally do in an array. However, the ash shell from busy box does not support arrays. Busybox does support awk. The following function is used to increment, decrement, and reset and array of counters of single digits stored as characters in a string.

#mod_field takes three parameters: OP INDEX DATA

#OP is the opperation: inc, dec, reset

#INDEX is the offset into the string from 1 to 9

#DATA is the state stored as a string

#OUTPUT is DATA with DATA[INDEX] modified

mod_field(){
OP=$1
INDEX=$2
DATA=$3

echo $OP $INDEX $DATA | \
awk ‘
{
VAL=substr($3,$2,1);
FIRST=substr($3,0,$2-1);
TAIL=substr($3,$2+1) ;
}
$1 ~ /inc/ { VAL++; }
$1 ~ /dec/ { VAL–; }
$1 ~ /reset/{ VAL=0; }
END{ print FIRST VAL TAIL;}
‘
}

#Here is how to call it:
DATA=0000000000
DATA=`mod_field inc 3 $DATA `
echo $DATA

#This should produce 0010000000

DATA=`mod_field dec 3 $DATA `
echo $DATA

#And set DATA back to 0000000000
for i in 1 2 2 3 4 4 4 4 5 6 6 7 8 8 8 8 8 8 9
do
DATA=`mod_field inc $i $DATA `
done
echo $DATA
#Should produce 1214121610

for i in 1 2 2 3 4 4 4 4 5 6 6 7 8 8 8 8 8 8 9
do
DATA=`mod_field dec $i $DATA `
done
echo $DATA

#Should produce 0000000000

DATA=1111111111111
DATA=`mod_field reset 3 $DATA`
echo $DATA

#Should produce 0000000000