Linux commands
Browse the directory structure
|
|
pwd |
tells you where you are |
ls |
list the content of the current directory |
ls <directory name> |
list the content of a directory |
cd <directory name> |
go to the specified directory |
cd ~ (or cd) |
go to your home directory |
cd .. |
go to the parent directory |
tree <directory name> |
list the content of a directory in a tree-like format |
mkdir <directory name> |
creates specified directory |
View the content of a file
|
|
less, more |
view text with paging |
head |
prints first lines of a file |
tail |
prints last lines of a file |
cat |
print content of a file into the screen |
zcat |
print content of a gzip compressed file |
File manipulations
|
|
rm <file name> |
remove file |
cp <file1> <file2> |
copy file1 into file2 |
mv <file1> <file2> |
rename file1 to file2 |
Some other useful commands
|
|
grep <pattern> |
show lines of text containing a given pattern |
grep -v <pattern> |
show lines of text not containing a given pattern |
sort |
sort linesof text files |
wc |
counting words, lines and characters |
> (output redirection) |
allows to redirect the output to a file |
\| (pipe) |
allows to send output from one program to another |
cut |
to extract portion of a file by selecting columns |
echo |
input a line of text and display it on standard output |
AWK programming
AWK - UNIX shell programming language. A fast and stable tool for
processing text files.
|
|
awk '/www/ { print $0 }' <file> |
search for the pattern ‘www’ in the each line of the file |
awk '$3=="www"' <file> |
search for pattern ‘www’ in the third column of the file |
awk 'length($0) > 80' <file> |
print every line in the file that is longer than 80 characters |
awk 'NR % 2 == 0' <file> |
print even-numbered lines in the file |
Some built-in variables
|
|
NR |
Number of records |
NF |
Number of fields |
FS |
Field separator character |
OFS |
Output field separator character |