Linux Administration Course

• cat /etc/passwd | awk -F: '{print $7}' | sort | uniq -c

• dino=rawr #not inherited
• export dino2=rawr2 #is inherited

• */5 * * * * 'echo "I love Linux" | wall'

• Users: /home/<username>
• Root: /root

• alias

• unalias
• alias

• grep scott /etc/shadow
• chage -l scott

• .bashrc or /etc/profile.d

• /etc/skel

• /etc/profile.d/

• cat /etc/passwd

• id <username>

• touch file.date +%F``
• touch file.$(date +%F%T)

• for i in $(seq 100); do touch file$i; done
• touch file{1..100}
• count=1;while [ $count -lt 100 ]; do touch file$count; count=$((count+=1)); done

• echo $$

• for i in seq 1 2 199; do echo "I am checking the number $i"; touch file$i; done

• var1=100

• watch uptime
• while true; do uptime; sleep 2; done

• seq 100
• seq 1 100
• count=1;while [ $count -le 100 ]; do echo "$count"; count=$((count+=1)); done
• for ((i=1;i<=100;i++)); do echo "I am counting $i"; done
• awk '{for (i=1;i<=100;++i)print i}' <<< ""
• perl -e '$count=0; while($count <= 100){print "$count\n"; $count++;}'
• perl -E 'for ($i=1; $i<=100; $i++){print "$i \n";}'
• perl -E 'for ($i=1; $i<=100; $i++){say $i;}'

• for server in controlplane node01; do echo "I am working on server $server"; done
• for server in $(cat servers); do echo "I am working on server $server"; done
• while read -r server; do echo $server; done < servers

• cat script.sh

  #!/bin/bash
  ####################################################
  # Purpose:
  # Date:
  # Name:
  # Revisions:
  ####################################################
  startTime=`date`
  sleep 10
  endTime=`date`
  echo "The start was $startTime and the end was $endTime"
  

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