Linux Commands

FIND TEXT
Find some text in folder files
grep --color=auto -nH 'text_to_find' *

Find some text in folder and subfolder files
grep -r --color=auto -nH 'text_to_find' *
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To generate a file with custom size:

# dd if=/dev/zero of=output.dat  bs=1024  count=10240

or
# dd if=/dev/zero of=output.dat  bs=1M  count=10

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 Copy BSD Disk to another

 dd if=/dev/ad0 of=/dev/da0 bs=1M

If you not have all disk in same plece you can try to make a dump over SSH

dump -C16 -b64 -0uanL -h0 -f - /    | gzip -2 | ssh -c blowfish user@host.com dd of=filename.dump.gz 

To restore you can try:

mount first partition

mount /dev/ad1s1a /tmp/root #(ad1 is the backup disk) 

  
ssh -c blowfish usr@host.com gzcat root.dump.gz | (cd /tmp/root && restore -ruf -)

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 #!/bin/bash
count=99
if [ $count -eq 100 ]
then
  echo "Count is 100"
elif [ $count -gt 100 ]
then
  echo "Count is greater than 100"
else
  echo "Count is less than 100"
fi

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show listen port by process

netstat -tupln

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show linux open files

lsof /dev/sda1

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show port listen by process

lsof -i :22

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Scan all ports with nmap

nmap -P0 -vv -sS -ff -r -n -p 1-65535 SERVER_IP_HERE

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List apache modules

apachectl -t -D DUMP_MODULES

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Show open files by process

 watch 'lsof -u apache | sort | uniq -c | sort -n'

 watch 'lsof -u apache | awk '\''{print $2}'\'' | sort | uniq -c | sort -n'