`head` prints the beginning of files or standard input. It is useful for quick previews and for limiting noisy pipeline output. ## Basics ### Print default lines Print the first 10 lines of a file. ```bash $ head file.txt line 1 line 2 line 3 line 4 line 5 line 6 line 7 line 8 line 9 line 10 ``` ### Print a fixed number of lines Use `-n` to choose how many lines to print. ```bash $ head -n 5 file.txt line 1 line 2 line 3 line 4 line 5 ``` ### Print a header row Print only the first line of a CSV or table-like file. ```bash $ head -n 1 users.csv id,name,role ``` ### Print multiple file starts When reading multiple files, `head` labels each file's output. ```bash $ head file1.txt file2.txt ==> file1.txt <== alpha beta ==> file2.txt <== one two ``` ## Bytes ### Print first bytes Use `-c` to limit by bytes instead of lines. ```bash $ head -c 100 file.txt Example ``` ## Common Pipelines ### Show newest files Sort a directory by modification time and keep the first few entries. ```bash $ ls -lt | head -n 5 total 24 drwxr-xr-x 5 alice staff 160 May 6 10:20 src -rw-r--r-- 1 alice staff 612 May 6 10:15 README.md ``` ### Show top CPU processes Sort processes by CPU usage and keep the top rows. ```bash $ ps aux | sort -k3,3nr | head -n 5 alice 4242 38.0 1.2 app-server alice 4170 12.5 0.8 node root 301 5.1 0.4 WindowServer ``` ### Preview matching log lines Limit a noisy grep result to the first matches. ```bash $ grep "ERROR" app.log | head -n 20 ERROR failed to connect ERROR retry limit reached ```