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How would you display the value of the present working directory?
The pwd command is used to display the current working directory.
How do you display the first line of a text file in Unix?
Type the following head command to display first 10 lines of a file named “bar.txt”:
- head -10 bar.txt.
- head -20 bar.txt.
- sed -n 1,10p /etc/group.
- sed -n 1,20p /etc/group.
- awk ‘FNR <= 10’ /etc/passwd.
- awk ‘FNR <= 20’ /etc/passwd.
- perl -ne’1..10 and print’ /etc/passwd.
- perl -ne’1..20 and print’ /etc/passwd.
When do you make a substitution in Bash?
Command substitution occurs when a command is enclosed as follows: $ ( command ) or. ` command `. Bash performs the expansion by executing command in a subshell environment and replacing the command substitution with the standard output of the command, with any trailing newlines deleted.
How does the read a file in Bash work?
Bash performs variable expansion on $FILE, enters command substitution, passes the value of $FILE to cat, cat outputs the contents of $FILE to standard output, command substitution finishes by replacing the entire line with the standard output resulting from the command inside, and Bash attempts to execute it like a simple command.
How to use command substitution in a shell?
Command substitution is an operation with dedicated syntax to both execute a command and to have this command’s output hold (stored) by a variable for later use. We can then print the result using the command printf: The command substitution syntax is $ (). The command itself is date.
How does the expansion in Bash take place?
Bash performs the expansion by executing command and replacing the command substitution with the standard output of the command, with any trailing newlines deleted. Embedded newlines are not deleted, but they may be removed during word splitting.