To display the first line of a file in Unix or Linux, you can use the head command with the -n 1 option.
Here is the basic syntax for using the head command:
head [-n lines] [file ...]
The -n option specifies the number of lines to display, and the lines argument is the number of lines to display. The file argument is the name of the file to display.
For example, to display the first line of the file file.txt, you can use the following command:
head -n 1 file.txt
This will display the first line of file.txt.
You can also use the head command without the -n option to display the first 10 lines of the file by default.
For example:
head file.txt
This will display the first 10 lines of file.txt.
Alternatively, you can use the sed command to display the first line of a file. The sed command is a stream editor that can be used to perform various text transformations on an input stream.
To display the first line of a file with sed, you can use the following command:
sed -n '1p' file.txt
This will display the first line of file.txt. The -n option tells sed to suppress automatic printing of pattern space, and the 1p command tells sed to print the first line (1)