basic bash commandspwd : print working directory | cd /path/to/dir : change direcotry | ls /dir/to/list : list directory content (default is .) | -1 : display the content on one column | -l : display the content with long listing format | -a : display the content of the directory (including hidden files) | -R : Display the content of the directory and the content of subdirectories | mv /path/to/file /path/where/to/move : move or rename a file or a directory | cp /path/to/file /path/where/to/copy : copy a file | -r : copy recursively (used to copy directory) | rm /path/to/file : remove a file | -r : remove recursively (used to remove directories) | -f : force remove | mkdir /path/dirName : create an empty directory | rmdir /path/to/dir : remove a directory (works only if the direcotry is empty) |
bash redirectionscommand > file : redirect stdout to file. (creates the file if it doesn't exist and overwrite it if it does exist) | command >> file : redirect stdout to file. (creates the file if it doesn't exist and append to the end it if it does exist) | command 2> file : redirect stderr to file (creates the file if it doesn't exist and overwrite it if it does exist) | command 2>> file : redirect stdout to file. (creates the file if it doesn't exist and append to the end it if it does exist) | command &> file : redirect stdout and stderr to file (creates the file if it doesn't exist and overwrite it if it does exist) | command &>> file : redirect stdout and stderr to file. (creates the file if it doesn't exist and append to the end it if it does exist) | command < file : redirect stdin to file. | command1 | command 2 : uses the output of command1 as the input of command2 |
file globbing regex\ : escape character. It deletes the signification of a special character | ? : Any character, once. | * : Any character, 0, 1 or many time. | [...] : Any character that is in the class. ex: [abc], [a-z], [0-9] | [^...]: Any character that is not in the class. ex: [^abc], [^a-z], [^0-9] | {s1, s2, sN} : match s1 or s2 or sN |
control structure (if)if <expression>; then
[statements]
elif <expression>; then
[statements]
else
[statements]
fi |
control structure (while)while <expression>; do
[statements]
done |
control structure (for)for var in <expression>; do
echo $var
[statements]
done |
control structure (case)# patterns are file globing regex
case <expression> in
pattern1)
[statements]
;;
pattern2)
[statements]
;;
*)
[statements]
;;
esac |
function definitionfunction functionName {
[statements]
[return X]
} |
conditional expressions&& : logical and operator | || : logical or operator | [[ string ]] : return 0 if string is not empty | [[ -z string ]] : return 0 if the string is empty | [[ string1 == string2 ]] : return 0 if the string are equivalent | [[ string1 != string2 ]] : return 0 if the string are not equivalent | [[ string =~ pattern ]] : return 0 if the string matches the pattern (extended regex) | [[ -e file ]] : return 0 if the file exists | [[ -d file ]] : return 0 if file is a directory | [[ -f file ]] : return 0 if file is a file | [[ -x file ]] : return 0 if file is executable | [[ $n1 -eq $n2 ]] : return 0 if $n1 == $n2 | [[ $n1 -lt $n2 ]] : return 0 if $n1 < $n2 | [[ $n1 -gt $n2 ]] : return 0 if $n1 > $n2 | [[ $n1 -ge $n2 ]] : return 0 if $n1 >= $n2 | [[ $n1 -le $n2 ]] : return 0 if $n1 <= $n2 | [[ $n1 -ne $n2 ]] : return 0 if $n1 != $n2 |
| | more basic bash commandspasswd : change your password | history : consult the history of your command | jobs : list of your pending proccesses | cat file1 file2 ... : concatenate files and print to stdout | more / less file1 file2 .. : diplsay a file page by page on stdout | tail / head number : display the "number" first or last line of a file on stdout | touch file1 file2 ... : change the modification date of the files | chmod : change the privileges of a file / directory | echo "text" : display a line of text to stdout | sort file1 file2 ... : sort the file (combine files if many are specified) and print the result to stdout (files aren't impacted) | -r : sort in reverse order | -n : numerical sort | -u : delete duplicated lines | wc file1 file2 ... : print to stdout the number of characters, words and lines of files | -l : number of lines only | -w : number of words only | -w : number of characters only | diff file1 file1 : compare file1 and file 2 for differences | -i : ignore the character case | -B : ignore empty lines | -w : ignore whitespaces | -c : add context to the output (good for readability) | which commandName : print the path of a command | pushd / popd /path/to/dir : change directory using the directory stack | dirs : print the directory stack | find /path/to/dir -name pattern : find every files and directory that have a name that matches "pattern" in the directory specified and its subdirectories | man commandName : Display the manual for command commandName | sudo command : run the command as superuser | command1 | xargs -i command2 : uses the output of the command1 as the input of the command2. output will be accessible via {} in command2 |
grep (simple regex)grep "pattern" file1 file2 ... : print the lines that matched the pattern | -v : print lines that didn't match the pattern | -i : ignore the character case | -l : print the name of the files that have at least one match | -o : print only the piece of line that matched the pattern | -E : uses the extended regex | -q : quiet. returns 0 in $? if at least one line has been matched. 1 if no line matched |
variablesVAR=VARVALUE : create a variable VAR. the variable can be accessed like so: $VAR or ${VAR} | VAR="$VAR2" : $VAR will contains the value of $VAR2 | VAR='$VAR2' : $VAR will contains $VAR2 | VAR=$(command) : $VAR will contains the output of the command | (( VAR = $VAR + 1 )): the double parentheses must be used when doing arithmetics | ${VAR#pattern} : return a substring of VAR where the smallest string (starting from the beginning) matching “pattern” will be cut | ${VAR##pattern} : return a substring of VAR where the longest string (starting from the beginning) matching “pattern” will be cut | ${VAR%pattern} : return a substring of VAR where the smallest string (starting from the end) matching “pattern” will be cut | ${VAR%%pattern} : return a substring of VAR where the longest string (starting from the end) matching “pattern” will be cut | $? : the exit status of the last command / function executed. usually 0 when everything went right. | $# : the number of args passed to the script / function | $0 : the name of the script | $n : the nth argument passed to the script / function | $@ : the list of all the argument passde to the script / function | Arrays | myArray=(value1 value2 value3): declare an array | declare -a myArray=(value1 value2 value3): declare an array | ${myArray[index]} : access an element (index starts at 0) | myArray[index]= : add or modify the element at index | ${#myArray[*]} : return the lenght of the array | ${myArray[*]}: all the elements of the array |
| | simple regex\ : escape character. It deletes the signification of a special character | . : joker. It represents any characters | * : 0, 1 or many repetition of the last character / sequence of character | ^ : The beginning of the line | $ : The end of the line | [...] : Any character that is in the class. ex: [abc], [a-z], [0-9] | [^...]: Any character that is not in the class. ex: [^abc], [^a-z], [^0-9] | \(...\) : Capture the pattern. The pattern can then be accessed with \1, \2 ... \n depending on the number of capture in the regex | \{n\} : n repetitions of the last character / sequence of character | \{n,\} : At least n repetitions of the last character / sequence of character | \{n, m\} : Between n and m repetitions of the last character / sequence of character |
extended regex\ : escape character. It deletes the signification of a special character | . : joker. It represents any characters | * : 0, 1 or many repetition of the last character / sequence of character | + : 1 or more repetition of the last character / sequence of character | ? : The last character / sequence of character can appear or not | ^ : The beginning of the line | $ : The end of the line | [...] : Any character that is in the class. ex: [abc], [a-z], [0-9] | [^...]: Any character that is not in the class. ex: [^abc], [^a-z], [^0-9] | s1|s2 : Either s1 or s2 but not both | (...) : change the priority | {n} : n repetitions of the last character / sequence of character | {n,} : At least n repetitions of the last character / sequence of character | {n, m} : Between n and m repetitions of the last character / sequence of character |
sed (simple regex)sed 'sed script' file : execute the script on every line of "file" | s/pattern/newString/gI : Substitute the piece of the line that matches "pattern" by "newString". g (optional): global, I (optional): ignore case | /pattern/d : delete the line if "pattern" is matched | /pattern/p : print the line if "pattern" is matched | /pattern1/,/pattern2/ : print every lines between the first line that matches "pattern1" to the first line that matches "pattern2" | -i.ext : Modifications done "in-place". A backup file will be created with .ext extension (it is optional) | -n : print only the lines that matched the pattern |
awk (extended regex)awk -Fc 'awk script' file1 file2 ... (where "c" is the delimiter) | typical awk script: 'BEGIN {statements} /pattern/ {script statements} END {statements}' | BEGIN {} : Will be executed once at the start | END {} : Will be executed once at the end | /pattern/ : only lines that matched the pattern will be processed | /pattern1/,/pattern2/ : every line from the first line that matches pattern1 to the first line that matches pattern2 will be processed | {script statements} : core of the script | printf: C-style formatter (man printf) | $n : the nth field of the line | $0 : the entire line | NR : the record number | NF : the number of fields in the record | FS: The field separator (the delimiter) |
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