View xml files like a pro
Viewing XML files can be daunting with tracking mentally where the tag starts and where it ends. So, I ended up with the following alias to help me view xml files
xmllint --format - | pygmentize -f 16m -O style=native -g
Add files to dropbox with single curl command
I have been thinking of posting this for sometime now. This is very useful, when you are working on a different Linux box and want to upload a file to dropbox.
So, before you run this command, you need to create your auth token in Dropbox developer API page. Once that is done, need to change the 2 parameters in command below. Export your Access token and run the below command.
Continue readingSplit pcap to multiple files based on number of packets
Here is a script that can use tshark to split a large pcap to multiple small pcaps
inpcap="test.pcap"
max=$(tshark -r $inpcap -n -T fields -e frame.number|tail -1)
# This is the number of packets in each split pcap
c=1
# Save all new pcaps to out, if it does not exist, create it.
[[ ! -d out ]] && mkdir out
for i in $(seq 1 $max $c)
do
tshark -r $inpcap -n -c $c "frame.number==$i" -w out/$i.pcap
#Do other stuff, if required
read -p "Send the next packet? "
done
A very simple 3-4 line script that has saved my day so may times.
Continue readingGREP_COLORS – change the colors in the GREP output.
Today we will look at the variable GREP_COLORS. This variable determines the colour that is used with the grep command. You can look at the man page of the grep command to see what the various options mean. Here is the excerpt from the man command:
GREP_COLORS
Specifies the colors and other attributes used to highlight various parts of the
output. Its value is a colon-separated list of capabilities that defaults to
ms=01;31:mc=01;31:sl=:cx=:fn=35:ln=32:bn=32:se=36 with the rv and ne boolean
capabilities omitted (i.e., false). Supported capabilities are as follows.
sl= SGR <a class="zem_slink" title="Substring" href="http://en.wikipedia.org/wiki/Substring" rel="wikipedia">substring</a> for whole selected lines (i.e., matching lines when the -v
command-line option is omitted, or non-matching lines when -v is specified).
If however the boolean rv capability and the -v command-line option are both
specified, it applies to context matching lines instead. The <a class="zem_slink" title="Default (finance)" href="http://en.wikipedia.org/wiki/Default_%28finance%29" rel="wikipedia">default</a> is
empty (i.e., the terminal's default color pair).
cx= SGR substring for whole context lines (i.e., non-matching lines when the -v
command-line option is omitted, or matching lines when -v is specified). If
however the boolean rv capability and the -v command-line option are both
specified, it applies to selected non-matching lines instead. The default
is empty (i.e., the terminal's default color pair).
rv <a class="zem_slink" title="Boolean data type" href="http://en.wikipedia.org/wiki/Boolean_data_type" rel="wikipedia">Boolean value</a> that reverses (swaps) the meanings of the sl= and cx=
capabilities when the -v command-line option is specified. The default is
false (i.e., the capability is omitted).
mt=01;31
SGR substring for matching <a class="zem_slink" title="Empty set" href="http://en.wikipedia.org/wiki/Empty_set" rel="wikipedia">non-empty</a> text in any matching line (i.e., a
selected line when the -v command-line option is omitted, or a context line
when -v is specified). Setting this is equivalent to setting both ms= and
mc= at once to the same value. The default is a bold red text foreground
over the current line background.
ms=01;31
SGR substring for matching non-empty text in a selected line. (This is only
used when the -v command-line option is omitted.) The effect of the sl= (or
cx= if rv) capability remains active when this kicks in. The default is a
bold red text foreground over the current line background.
mc=01;31
SGR substring for matching non-empty text in a context line. (This is only
used when the -v command-line option is specified.) The effect of the cx=
(or sl= if rv) capability remains active when this kicks in. The default is
a bold red text foreground over the current line background.
fn=35 SGR substring for file names prefixing any content line. The default is a
magenta text foreground over the terminal's default background.
ln=32 SGR substring for <a class="zem_slink" title="Line number" href="http://en.wikipedia.org/wiki/Line_number" rel="wikipedia">line numbers</a> prefixing any content line. The default is a
green text foreground over the terminal's default background.
bn=32 SGR substring for byte offsets prefixing any content line. The default is a
green text foreground over the terminal's default background.
se=36 SGR substring for separators that are inserted between selected line fields
(:), between context line fields, (-), and between groups of adjacent lines
when nonzero context is specified (--). The default is a cyan text
foreground over the terminal's default background.
ne Boolean value that prevents clearing to the <a class="zem_slink" title="Newline" href="http://en.wikipedia.org/wiki/Newline" rel="wikipedia">end of line</a> using Erase in Line
(EL) to Right (\33[K) each time a colorized item ends. This is needed on
terminals on which EL is not supported. It is otherwise useful on terminals
for which the back_color_erase (bce) boolean terminfo capability does not
apply, when the chosen highlight colors do not affect the background, or
when EL is too slow or causes too much flicker. The default is false (i.e.,
the capability is omitted).
copy /proc folder
Other day, I was trying to copy the proc folder with following command:
tar cvzf /tmp/proc.tgz /proc
and I found out that all the files in tar were empty. Strange it may seem but lot of people are facing this as /proc is not a regular filesystem, so I wrote a quick script to copy the proc folder. Here is the script:
cd /
mkdir /tmp/proc
[[ -z $1 ]] && exit -1
find /proc/$1/ -not -name pagemap | while read F ; do
D=/tmp/$F
if [[ -d $F ]]
then
echo "$(ls -ld $F) => Directory"
mkdir -p $D
fi
if [[ -L $F ]]
then
echo "$(ls -ld $F) => copied"
cp -P $F /tmp/$F
elif [[ -f $F ]]
then
echo "$(ls -ld $F) => Cat"
cat $F > /tmp/$F
else
echo "Dont know $F"
fi
done
cool sed/grep magic to convert output to csv format
I generallly keep doing this a lot, so thought will share with you. Lets assume we are capturing free ouput every min/hour/or whatever. The output looks like this:
Time: Mon Jan 21 23:59:10 AEDT 2019
——————-total used free shared buff/cache available
Mem: 32014 8656 1735 1697 21621 21308
Swap: 51195 75 51120
then we can use some grep and sed to convert this to something like this:
Mon Jan 21 23:59:10 AEDT 2019,32014,8656,1735,1697,21621,21308
Continue reading
bash function for rpm whatprovides
Sometimes some simple one-liner function can save you a lot of time, like-
wps ()
{
rpm -q --whatprovides $(which $1 )
} # ---------- end of function wps ----------