Notable Linux Command Line Commands
Convert Ascii Hex to Binary
cat
Date Command Helpful Help alias dateh='date --help|sed -n "/^ *%%/,/^ *%Z/p"|while read l;do date +\ %${l/% */}:|" |${l/% /}|$ {l# }";done|column -s"|" -t'
Make Fifo file mkfifo /tmp/debug_file.log cat /tmp/debug_file.log > /nfs/trace.log & #Don't forget the "&" to send this to the background
Let someone watch your shell session script -f >(nc -l -p 5000) #On Host telnet host 5000 #On Watcher
Pipe Through SSH to dump to file grep -A 5 "something" * | \grep -ho "->.*," | ssh user@hostname "tee -a /tmp/tim.txt"
Look Busy
for f in seq 0 100;do echo $f | dialog --backtitle "Package Installation" --title "Package Installation
Status" --gauge "Installing..." 6 40; sleep 10; done
Start VNC Server for Display :0.0 x0vncserver PasswordFile=/home/username/.vnc/passwd display=:0.0
Send Xmessage to Main X Console from Remote System ssh user@hostname xmessage -display :0.0 -center "Test Message"
Tar through ssh if you can't access companion tar cf - /nfs/test.log | ssh user@hostname "(cd /tmp; tar xf -)"
Spy on a shell process ps aux | grep sh strace -ff -e write=1,2 -s 1024 -p $PID 2>&1 | grep "^ |"
Convert Number between Hex & Decimal function hex2dec(){ printf "%d\n" $1; } function dec2hex(){ printf "0x%x\n" $1; }
Run a command with no output dumped to screen nohup cat /tmp/tgh.txt function silent(){ $@ > /dev/null 2>&1; }
Diff Output of 2 commands gvimdiff <(cat test.txt | grep tmp) <(cat test2.txt | sed 's/tom/tmp/g' | grep tmp); #As .bashrc function function fdiff(){ gvimdiff <($1 $2) <($1 $3); } #Easier to make it a function, but less flexible
Fix output so it goes into a nice table format col
Remove (Binary) Control Characters from a file for grep-ping cat somefile.txt | strings | grep “xx”
Split Pipe into multiple pipes to work on echo "tee can split a pipe in two"|tee >(rev) >(tr ' ' '_')
Get Assembly from a executable objdump -b binary -m i386 -D shellcode.bin
Simulate Typing dmesg|while read x;do for((i=0;i<${#x};i++));do echo -n "${x:$i:1}";sleep .06;done;echo;done tail -f /tmp/ppp |while read x;do for((i=0;i<${#x};i++));do echo -n "${x:$i:1}";sleep .01;done;echo;done
Snowstorm
while true ; do NUM=$((
Run Command(s) Once, at Given Time in the future at 5:00 at> Fix -complete -defect 731721 -release fips720 -component esw_vadj at> Fix -complete -defect 731721 -release fips720 -component esw_powr at> job 50 at 2009-11-20 05:00 at -l #List AT job(s) atrm 50 # Terminate AT job
Remote Telnet Port Forward (FSP=10.10.10.10, behind system hostname) ssh -L 12345:10.10.10.10:23 user@hostname telnet localhost 12345
Process Tree psu(){ command ps -Hcl -F S f -u ${1:-$USER}; }
Random Hex Digits ran=$(head /dev/urandom | md5sum); echo ${ran:0:2}:${ran:3:2}:${ran:5:2}:${ran:7:2};
Reuse all parameters of the previous command line !*
Diff output of 2 commands w/o using temp files b=$(grep Tim .vimrc); a=$(grep "Tim|expand" .vimrc); gvimdiff <(echo "$a") <(echo "$b")
SCP back to Home Dir on Host SSH'd in from scp /path/to/file ${SSH_CLIENT%% *}:
Grab & Display Screenshot import screenshot.jpg && display screenshot.jpg
Histogram Graph on the Command Line \grep somefile.txt | \grep -o " ..:.." | sed 's/:/ /g' | sed 's/^ .. //g' | sort | uniq -c | awk '{ printf("%s\t%s\t",$2,$1) ; for (i = 0; i < $1; i++) {printf("*")}; print "" }'
Quickly graph list of numbers gnuplot -persist <(echo "plot '<(sort -n listOfNumbers.txt)' with lines")
Recurse through subdirs, run command in every subdir for f in $(find ./ -type d); do pushd $f; pwd; popd; done
Ddate - Discordian Calendar ddate
Display a block of text with AWK awk '/start_pattern/,/stop_pattern/' file.txt
Base conversions with bc echo "obase=2; 27" | bc -l
Display the standard deviation of a column of numbers with awk awk '{sum+=$1; sumsq+=$1*$1} END {print sqrt(sumsq/NR - (sum/NR)**2)}' file.dat
Averaging Columns of Numbers awk '{sum1+=$1; sum2+=$2} END {print sum1/NR, sum2/NR}' file.dat
Stopwatch time cat <Ctrl+D> to stop
Put Term into VI mode set -o vinet
Display bytes that are different in hex cmp -l file1.bin file2.bin | awk '{print $1, "0"$2, "0"$3}' | gawk --non-decimal-data '{printf("0x%08x 0x%02x 0x %02x\n",$1,$2,$3);}'
Display bytes that are different in hex & ascii cmp -l file1.bin file2.bin | awk '{netprint $1, "0"$2, "0"$3}' | gawk --non-decimal-data '{printf("0x%08x 0x %02x0x%02x %d %d\n",$1,$2,$3,$2,$3);}' | gawk --non-decimal-data '{printf("0x%08x 0x%02x 0x%02x %c %c\n", $1,$2,$3,$4,$5);}' | more
Count bytes that are different between two binary files cmp -l tpmd_dump.bin tpmd_fips710_hv32_3042.bin | wc -l
All Output to file cat file > startx.log 2>&1
Disown a background process so it doesn't close after shell closes <Ctrl+Z> bgnet disown
Merge *.pdf Files
gs -q -sPAPERSIZE=letter -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=out.pdf ls *.pdf
Rapidly invoke an editor to write a long command <Ctrl+x> <Ctrl+e>
Mount a Temporary RAM partition mount -t tmpfs tmpfs /mnt -o sinetze=1024m
Processes by CPU usage ps -e -o pcpu,cpu,nice,state,cputime,args --sort pcpu | sed "/^ 0.0 /d"
SSH connection through host in the middle ssh -t reachable_host ssh unreachable_host
Screen Log Sessions screen -D -R -L
Pipe to Vim cat foo.txt | vim - cat foo.txt | vim -R -
Save a file you edited in vim without the needed permissions :w !sudo tee %
Get List of all Keyboard Shortcuts in Screen Ctrl+A ?
Background a SSH-session: RETURN~&
Close a SSH-session: RETURN~.
Show other options:net RETURN~?
Create script of last command echo "!!" > foo.sh
Fork Bomb :(){ :|:& };:
Reconnect to screen w/o disconnecting screen -xR
Edit over SCP vim scp://username@host//path/to/somefile
Open on port 6506 & dump *.txt on connection nc -w 10 -v -l -p 6506 < ./public/somefile.txt
Empty the linux buffer cache sync && echo 3 > /proc/sys/vm/drop_caches
Dump output to nohup.out & background & dont' kill if detached session nohup &
Run last command as root sudo !!
Get list of programs listening on ports netstat -plunt
Run "unaliased" rm \rm
Wham! Reboot echo 1 > /proc/sys/kernel/sysrq; echo b > /proc/sysrq-trigger
Show lines that appear in both file1 & file2 comm -1 -2 <(sort file1) <(sort file2)
Watch video in terminal mplayer -vo caca out.mpg Top 10 Memory Hogs ps aux | sort -nk +4 | tail
Backdoor to Allow Remote Shell nc -vv -l -p 1234 -e /bin/bash connect with: nc localhost 1234
Browse RAM sudo cat /proc/kcore | strings | awk 'length > 20' | less
Remote Screen ssh -t user@some.domain.com /usr/bin/screen -xRR
Binary Injection echo -n $HEXBYTES | xxd -r -p | dd of=$FILE seek=$((0x$OFFSET)) bs=1 count=$NUMBYTES conv=notrunc Replace (as opposed to insert) hex opcodes, data, breakpoints, etc. without opening a hex editor. HEXBYTES contains the hex you want to inject in ascii form (e.g. 31c0) NUMBYTES is the number of bytes in HEXBYTES (in the previous example, this would be 2) OFFSET is the hex offset (e.g. 49cf) into the binary FILE Edit: The count argument to dd can be omitted.