Difference between revisions of "Linux"

Revision as of 06:28, 22 January 2013

These topics have their own pages.

Getting Started

Scripting

Gnuplot

Common C, C++, FORTRAN Libraries

Useful Commands

The following is a (short) list of useful command when manipulating data in text files. Some common options are listed, but may not be explained. For full descriptions of each command, see the man page. stdin, stdout, and stderr refer to standard input, output and error, respectively.

ls [dir]

list the contents of a directory to stdout

if no directory is given, the contents of the current directory are listed

common options: -l, -a

cd [dir]

change current working directory to a directory. i.e. go into a directory

used to navigate the filesystem

cat [file1 [ file2 [...] ] ]

print text file(s) to stdout. if multiple files are given, their text is concatenated

useful for starting a pipeline of commands from the contents of a text file

echo [args...]

print arguments to stdout

useful for starting a pipeline of commands from a variable's value

useful for printing output to the terminal from inside a script

sort

read from stdin, sort lines, and write to stdout

common options: -k, -t, -n, -g

cut

read from stdin and write selected columns to stdout.

common options: -d, -f

column

read from stdin and write to stdout such that columns are aligned

common options: -t

head [file]

read from stdin, or from a file, and print the first 10 lines

useful for taking a peak at the contents of a large file

useful for limitng the output of a pipeline

common options: -n

tail [file]

read from stdin, or from a file, and print the last 10 lines

similar uses to head

can be used with head to print a single line, or range of lines, in a file

common options: -n

sed 's/old/new/g' [file]

read from stdin, or from a file, and replace all occurances of 'old' with 'new', then print to stdout