Useful commands and scripts (Linux, Windows, bash, etc...)

Linux

Automatically call 'ls' when the directory is changed:

sudo echo export 'PROMPT_COMMAND='\''[[ $my_currdir != $PWD ]] && ls; my_currdir=$PWD'\''' > ~/.bash_aliases

Reinstall all installed packages with a specific word: (in this case, this line reinstalls all installed packages with the word perl in it)

sudo apt-get --reinstall install $(dpkg --get-selections | grep perl | awk '{print $1}')

(this case, this line reinstalls all installed packages with the word perl in it and not perl-base)

sudo apt-get --reinstall install $(dpkg --get-selections | grep perl | grep -v perl-base | awk '{print $1}')

Update all opkg packages

for pkg in `opkg list-upgradable | cut -d' ' -f1 | grep -v Multiple`; do opkg upgrade $pkg; done

Find all files in home directory larger than a defined size

find ~ -size 20MB

Find occurences of ip address by count:

grep -o '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}' NCL-G2-LOG-1.txt | sort -r | uniq -c | sort -rn | head

Encrypted netcat group chat:

server: 

while true; do read -n30 ui; echo $ui |openssl enc -aes-256-cbc -a -k PaSSw; done | nc -l -p 8877 | while read so; do decoded_so=`echo "$so"| openssl enc -d -a -aes-256-cbc -k PaSSw`; echo -e "Incoming: $decoded_so"; done

client: 

while true; do read -n30 ui; echo $ui |openssl enc -aes-256-cbc -a -k PaSSw; done | nc $ipaddress 8877 | while read so; do decoded_so=`echo "$so"| openssl enc -d -a -aes-256-cbc -k PaSSw`; echo -e "Incoming: $decoded_so"; done

Centos issues:
when attempting to do an ssh-keygen as a user that is not in the sudoers file you will get a "permission denied" error because SELinux is blocking ssh-keygen. To get SELinux to accept the command without blockage, run the following:

chcon -R -t ssh_home_t ~/.ssh

Docker pull all and update all images from repositories:

docker images | awk 'NR > 1 && $1 !~ /<none>/ {print $1}' | uniq | xargs -n 1 docker pull

Mac

dd with a progress bar (requires brew and install pv):

pv -tpreb ~/Desktop/openSuse.img | sudo dd of=/dev/disk2 bs=1m

mount smb share:

mount_smbfs

or

mount -t smbfs

Windows

Flush Windows Updates cache:

net stop wuauserv
cd /d %windir%
rd /s SoftwareDistribution
net start wuauserv

Bash scripts

Auto extract compressed file (place the following in your bash_profile or bashrc file):

extract() { 
    if [ -f $1 ] ; then 
      case $1 in 
        *.tar.bz2)   tar xjf $1     ;; 
        *.tar.gz)    tar xzf $1     ;; 
        *.bz2)       bunzip2 $1     ;; 
        *.rar)       unrar e $1     ;; 
        *.gz)        gunzip $1      ;; 
        *.tar)       tar xf $1      ;; 
        *.tbz2)      tar xjf $1     ;; 
        *.tgz)       tar xzf $1     ;; 
        *.zip)       unzip $1       ;; 
        *.Z)         uncompress $1  ;; 
        *.7z)        7z x $1        ;; 
        *)     echo "'$1' cannot be extracted via extract()" ;; 
         esac 
     else 
         echo "'$1' is not a valid file" 
     fi 
}