| title | DevOps: Day 9 | |
|---|---|---|
| tags |
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- Some commonly used shell commands are:
- ls, pwd, cp, mv, touch, mkdir, find, top, ps -ef etc.
- Write a simple shell script to list all processes:
- ps -ef For just the process ID (which let's say in column 2):
- ps -ef | awk -F" " '{print $2}'
- Write a script to print only errors from a remote log:
- curl | grep . Hence we can achieve this by using curl(retrieves entire log file), grep is getting just the error portion of the log file and pipe(|) command which sends the output of curl to grep.
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Write a shell script to print numbers divisible by 3 and 5 not 15.
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Write a script to print number 's' in mississippi.
- x=mississippi
- grep -o "s" <<<"$x" | wc -l
- How will you debug the shell script
- set -x at the beginning of shell script.
- What is crontab in Linux? can you provide an example of usage?
- This is when you want an activity to be carried out automatically on linux, for example sending the health information of the server/node every 6am in the morning.
- How to open a read-only mode:
- vim -r
- What is the difference between hard link and soft link:
- Using hard link, you can create copy or mirror original file. Hard link will create a copy, even if the actual file is deleted from storage, hard link will keep a backup of your file.
- Soft link is for creating alias file.
Note: Always use examples to explain interview questions.
- What is the difference between break and continue statement:
- Break = breaking the exexution
- continue = continue the execution, but skip this and continue execution after skipping present condition.
- What are some of the disadvantages of shell scripting:
- Errors are frequent and costly, just a single error can totally halt the execution of the script.
- The execution speed is slow.
- Bugs or inadequacies in the languages' syntax/implementation.
- Large/Complex task are not suited for it.
- Provides minimal data structures.
- Everytime a shell command is executed, a new process is launched.
- What are the different types of loops and when to use:
- For, While, Do While loop.
- Is bash dynamically or statistically typed:
- it is dynamically typed. Because it doesn't need you to indicate the type you are working with.
- Explain about a network troubleshooting utility.
- traceroute: used for network debugging.
- traceroute
- tracepath: also used. Doesn't require root privileges.
- How will you sort list of names in a file?
- Use the sort command.
- How will you manage logs of a system that generates huge log files everyday.
- logrotate command.