Bash-interesting-command-examples

Interesting one-liners

• Find all drives and ignore loop devices

root@kvm03:/var/log# lsblk | grep -v "loop\|NAME" | grep "^[a-z]\|^[A-Z]" | awk '{print $1}'
sda
sdb
root@kvm03:/var/log# 

root@kvm03:/var/log# lsblk | grep disk | awk '{print $1}'
sda
sdb
root@kvm03:/var/log# 

Continue match until match is found

• This is using awk, and seems quite powerful as a tool
• found this little gem at Stack Exchange

awk '/Word A/,/Word D/' filename

/From/CONTINUE/Until/

• Remove non-english directories
• change the type to f if you are looking for non-english files
• ALWAYS test find results before deleting, duh!

sudo find . -type d -not -name "[a-zA-Z0-9]*" -exec rm -rf {} \;

Who the hell thought it was a good idea to NOT have xml2 available in both Mac and Linux? What the hell!?!?

• On Mac install gawk via brew
• will leverage xmllint, and then stupidity ensues... WTF?
• never trust this in prod-ish servers without a lot of testing. chatGPT gave this suggestion as a workaround to get the xml2 behavior.
• I am betting that complex xml will make this choke or turn into a pumpkin but meh, it works well enough for simple stuff.

echo '<root><name>Chris</name></root>' | xmllint --format - 2>/dev/null | gawk '
  /<[[:alnum:]_:-]+>/ {
    tag = gensub(/.*<([[:alnum:]_:-]+)>.*/, "\\1", "g")
    path = (path ? path "/" tag : "/" tag)
  }
  /<\/[[:alnum:]_:-]+>/ {
    if ($0 ~ /<[[:alnum:]_:-]+>[^<]+<\/[[:alnum:]_:-]+>/) {
      val = gensub(/.*<[[:alnum:]_:-]+>([^<]+)<\/[[:alnum:]_:-]+>.*/, "\\1", "g")
      print path "=" val
    }
    sub(/\/[^/]+$/, "", path)
  }'