Description : prints output of first part of the file by default it will print first 10 lines
Syntax : head filename
examples:
1. head upcasting.java
it will print first 10 lines of the file upcasting.java by default.
2. head -n 50 upcasting.java
it will print first 50 lines of the file upcasting.java.
3. head upcasting.java downcasting.java
it will print first 10 line of the 2 files upcasting.java and downcasting.java.
4. head *.java
it will print all the java files first 10 lines.
5. head *.java *.class
it will print all the java and class files first 10 lines.4. head *.java
it will print all the java files first 10 lines.
5. head *.java *.class
Tail Command:
Description : prints output of last part of the file by default it will print last 10 lines
Syntax : tail filename
Examples:
1. tail upcasting.java
it will print last 10 lines of the file upcasting.java by default.
2. tail -n 50 upcasting.java
it will print last 50 lines of the file upcasting.java.
3. tail upcasting.java downcasting.java
it will print last 10 line of the 2 files upcasting.java and downcasting.java.
4. tail *.java
it will print all the java files last 10 lines.
5. tail *.java *.class
it will print all the java and class files last 10 lines.4. tail *.java
it will print all the java files last 10 lines.
5. tail *.java *.class
Practice Examples:
1. How to Print the 11th line of the file ?
head -n 11 upcasting.java | tail -n 1
2. How to print lines from 5 to 11th of the file ?
head -n 11 upcasting.java | tail -n 5
3. How to print number of lines head and tail command file (by default it will print 10 lines)?
head upcasting.java | wc -l
tail upcasting.java | wc -l
both will return 10
head -n 20 upcasting.java | wc -l
tail -n 20 upcasting.java | wc -l
both will return 20
for number of word wc -w and number of characters wc -c
head upcasting.java | wc -c
it will print number of first 10 lines characters in digits
tail upcasting.java | wc -c
it will print number of last 10 lines characters in digits
head upcasting.java | wc -w
it will print number of first 10 lines words in digits
tail upcasting.java | wc -w
it will print number of last 10 lines words in digits
4. How to get First and last 5 files of java in a java directory?
ls *.java | tail -n 5
ls *.java | head -n 5
ls -l *.java | tail -n 5
ls -l *.java | tail -n 5
ls -l *.java | head -n 5
5. ls -la *.class | tail -n 12 | wc -l it will return 12
6. ls -la *.class | tail -n 12
it will shows last 12 class files list
7. ls -la *.class | head -n 12
5. ls -la *.class | tail -n 12 | wc -l it will return 12
6. ls -la *.class | tail -n 12
it will shows last 12 class files list
7. ls -la *.class | head -n 12
it will shows first 12 class files list.
8. head -c 10 downcasting.java
9. tail -c 10 downcasting.java
10. head -c 400 downcasting.java | tail -n 3
8. head -c 10 downcasting.java
9. tail -c 10 downcasting.java
10. head -c 400 downcasting.java | tail -n 3
(updates still come)
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