Lesson 7 / 29

Viewing File Contents

cat, less, head and tail.

cat — dump the whole file

cat prints a file's entire contents to the screen — fine for short files.

cat /etc/hostname

Output:

ubuntu-server

less — page through big files

less opens a file for scrollable viewing without loading it all into memory. Press q to quit, /word to search.

less /var/log/syslog

head & tail

head shows the first lines, tail the last. tail -f follows a growing file live — great for watching logs.

head -n 5 access.log
tail -f access.log

Quick check: Which command lets you watch a log file update live?

  • cat log.txt
  • tail -f log.txt
  • head log.txt
Answer

tail -f log.txt — `tail -f` keeps the file open and prints new lines as they're appended.