Tutorials

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1. List the files in current directory sorted by size?

- ls -l grep ^- sort -nr

2. List the hidden files in current directory?

- ls -a1 grep “^\.”

3. Delete blank lines in a file?

- cat sample.txt grep -v ‘^$’ > new_sample.txt

4. Search for a sample string in particular files ?

- grep .Debug. *.confHere grep uses the string .Debug. to search in all files with extension..conf. under current directory.

5. Display the last newly appending lines of a file during appendingdata to the same file by some processes ?

- tail .f Debug.logHere tail shows the newly appended data into Debug.log by some processes/user.

6. Display the Disk Usage of file sizes under each directory in current Directory ?

- du -k * sort .nr (or) du .k . sort -nr

7. Change to a directory, which is having very long name ?

- cd CDMA_3X_GEN*Here original directory name is . .CDMA_3X_GENERATION_DATA..

8. Display the all files recursively with path under current directory ?

- find . -depth -print

9. Set the Display automatically for the current new user ?

- export DISPLAY=`eval ‘who am i cut -d”(” -f2 cut -d”)” -f1′`Here in above command, see single quote, double quote, grave ascent is used. Observe carefully.

10. Display the processes, which are running under your username ?

- ps .aef grep MaheshvjHere, Maheshvj is the username.

11. List some Hot Keys for bash shell ?

- Ctrl+l . Clears the Screen. Ctrl+r . Does a search in previously given commands in shell. Ctrl+u - Clears the typing before the hotkey. Ctrl+a . Places cursor at the beginning of the command at shell. Ctrl+e . Places cursor at the end of the command at shell. Ctrl+d . Kills the shell. Ctrl+z . Places the currently running process into background.

12. Display the files in the directory by file size ?

- ls .ltr sort .nr .k 5

13. How to save man pages to a file ?

- man col .b > Example : man top col .b > top_help.txt

14. How to know the date & time for . when script is executed ?

- Add the following script line in shell script.eval echo “Script is executed at `date`” >> timeinfo.infHere, .timeinfo.inf. contains date & time details ie., when script is executed and history related to execution.

15. How do you find out drive statistics ?

- iostat -E

16. Display disk usage in Kilobytes ?

- du -k

17. Display top ten largest files/directories ?

- du -sk * sort -nr head

18. How much space is used for users in kilobytes ?

- quot -af

19. How to create null file ?

- cat /dev/null > filename1

20. Access common commands quicker ?

- ps -ef grep -i $@

21. Display the page size of memory ?

- pagesize -a

22. Display Ethernet Address arp table ?

- arp -a

23. Display the no.of active established connections to localhost ?

- netstat -a grep EST

24. Display the state of interfaces used for TCP/IP traffic ?

- netstat -i

25. Display the parent/child tree of a process ?

- ptree Example: ptree 1267

26. Show the working directory of a process ?

- pwdx Example: pwdx 1267

27. Display the processes current open files ?

- pfiles Example: pfiles 1267

28. Display the inter-process communication facility status ?

- ipcs

29. Display the top most process utilizing most CPU ?

- top .b 1

30. Alternative for top command ?

- prstat -a