Linux

introduction to sed and awk many Linux users and administrators will write scripts using comprehensive scripting languages such as Python and perl, rather than use sed and awk. However, the utilitites that are described here are much lighter;i.e. they use fewer system resources, and execute faster. sed abbreviation for stream editor. data from an input source/file (or stream) is taken and moved to a working space. the entire list of operations/modifications is applied over the data in the working space and...

working with large files directly opening the file in an editor will probably be inefficient (due to high memory utilization) because most text editors usually try to read the whole file into memory first. instead, one can use less to view the contents of such a large file, scrolling up and down page by page, without the system having to place the entire file in memory before starting. less somefile cat somefile | less head reads the first few lines...

cat cat read / write / concatenate tac prints the lines of a file in reverse order. each line remains the same, but the order of lines is inverted. cat > file cat » file (any subsequenet lines are appended to the file, until CTRL-D is typed) using cat interactively echo -e option, along with the following switches, is used to enable special character sequences, such as the newline character or horizontal tab

elevating to root account sudo configuration files are stored in the /tec/sudoers file and in the /etc/sudoers.d directory. by default, the sudoers.d directory is empty

filesystems lick /proc are called pseudo filesystems because they exist only in memory /var may be put in its own filesystem so that growth can be contained and not fatally affect the ststem /boot contains the basic files needed to boot the system