- List the files in current directory sorted by size ? - ls -l | grep ^- | sort -nr
- List the hidden files in current directory ? - ls -a1 | grep "^\."
- Delete blank lines in a file ? - cat sample.txt | grep -v ‘^$’ > new_sample.txt
- 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.
- 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.
- Display the Disk Usage of file sizes under each directory in currentDirectory ? - du -k * | sort –nr (or) du –k . | sort -nr
- Change to a directory, which is having very long name ? - cd CDMA_3X_GEN*Here original directory name is – “CDMA_3X_GENERATION_DATA”.
- Display the all files recursively with path under current directory ? - find . -depth -print
- 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.
- Display the processes, which are running under yourusername ? - ps –aef | grep MaheshvjHere, Maheshvj is the username.
- 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.
- Display the files in the directory by file size ? - ls –ltr | sort –nr –k 5
- How to save man pages to a file ? - man
| col –b > Example : man top | col –b > top_help.txt
- 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.
- How do you find out drive statistics ? - iostat -E
- Display disk usage in Kilobytes ? - du -k
- Display top ten largest files/directories ? - du -sk * | sort -nr | head
- How much space is used for users in kilobytes ? - quot -af
- How to create null file ? - cat /dev/null > filename1
- Access common commands quicker ? - ps -ef | grep -i $@
- Display the page size of memory ? - pagesize -a
- Display Ethernet Address arp table ? - arp -a
- Display the no.of active established connections to localhost ? - netstat -a | grep EST
- Display the state of interfaces used for TCP/IP traffice ? - netstat -i
- Display the parent/child tree of a process ? - ptree
Example: ptree 1267
- Show the working directory of a process ? - pwdx
Example: pwdx 1267
- Display the processes current open files ? - pfiles
Example: pfiles 1267
- Display the inter-process communication facility status ? - ipcs
- Display the top most process utilizing most CPU ? - top –b 1
- Alternative for top command ? - prstat -a