Unix Commands - Beginning Flashcards
kernel
manages processes, devices, and memory.
shell
interface between kernel and user. interpreter of commands.
file system
hierarchy of directories, subdirectories and files.
standard input
what user types.
standard output
resulting text from the process of a command.
passwd
command for password. password is not visible in shell. login is lowercase. commands are case sensitive.
logout
ends session
pwd
print working directory. shows pathway of current directory.
cd
change directory. can accept argument.
flags
single letter abbreviations that modify commands.
arguments
typically file names input after a command.
ls
lists directories and all files. -a lists all entries.
-l (lowercase L)
prints list in long format. gives mode, links. owner, size and time of last mod.
-F
visualization of contents being linked. these are / after names of directories. * is executable file. @ is link.
-1 (number one)
prints each file name on separate line.
-d
lists directory names without contents
-h
human readable. prints sizes in easy formats. flags do not require arguments and can be input together.
mkdir
make directory. argument is required. needs to know name of directory to create.
-p
parent. creates all files in directory that do not yet exist.
-cat
concatenate - writes the specified file as argument to standard output.
more [file]
writes the specified file as an argument to std output one screen at a time.
head [count] [file]
prints a certain number of lines from the specified output file. if not specified then standard number is ten.
tail [-f] [-c number] [-n number]
prints the lines of a specified file beginning at a certain place. if no flags are indicated, then default is ten lines.
sort
sorts files based on sorting criteria. ordered in ascending order as default. -r for reverse sorting. -n sorts lines numerically.