Lecture 10
Basic Commands
pwd, cd, ls, touch, less, history, cp, mv, echo, cat, whoami, mkdir, rmdir, rm ,locate, man, which, whatis, whereis, alias
rm -rf :- r stands for recursive (means it will delete nested folder) Note:-
sudo updatedb:- it is a command use to update filesystem database.
which:- it is a command use to find anything(programming)is intsalled or not on the system.eg:-which python
whatis:- it is a command use to know about any command.eg:- whatis ls
history -c :- it is use to clear all history of commands
whereis:- where command is the name of the command you want to search for
Lecture 11
0-stdin,
1-stdout,
2-stderr,
pipe, tee, cut, head, tail, sort, grep, uniq , wc, nl, file
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To find files from entire computer:- find / -type f -name filename.txt 2>/dev/null
find- stands for search
/- it means search entire computer
-type f name - it means we searching for specific file
2- stands for stderr
> redirecting
/dev/null/- it is like black hole , so that we cannt get any error(all the errors will be stored in this directory)
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tee:- if we want see the content of a file and at that time we also want to store the output in another file , we can use ths command.eg;- ls | tee output.txt
cut:- it use to print the character of any word/sentence.eg:- cat file.txt | cut -c 1
nl :- is used for print number lines in a file.eg:- nl file.txt
head:- is used for print number of line from a file(from starting).eg:- head -n 3 file.txt
tail:- is used for print number of line from a file(from last).eg:- tail -n 3 file.txt
wc:- is used to print the no. of line, word, and character.eg:- wc -l, -w, -c, file.txt
grep:- is used to print any matching word/pattern in any file. eg:- cat file.txt | grep "hello"
Lecture 12
