Unix Questions & Answers- Part 1

[wacky]

1) What switches can you give to the ls command to sort the output in time-modified order?

ls -t or ls -rt for reversed order. We can also add -l switch for long listing

2) What does the script command do?

script command writes all keyboard input and command output of a session to a file

3) I have a file called wacky.backup.tgz ,how would you extract the contents of this file?

tar -xzf wacky.backup.tgz

4) How would you list the names of the files in /etc that contained the string 'hostname' ?

This question is slightly confusing. String 'hostname' is in the file.

grep -l 'hostname' /etc/*


5) Given a plain text file, how would you remove all the newline characters so that the whole file appeared as one long line?

cat <filename> | tr -d '\n' > filename

There are other ways of doing this - sed, awk, perl

Please feel free to comment on any of this.

[ranatanveer]

being a system admin, no one remember the exact command, every one google out for exact syntax what he is looking for

[lambda]

being a system admin, no one remember the exact command, every one google out for exact syntax what he is looking for

yes, but those questions are so trivial that you'd better know the answers.

[LinuxFreaK]

Dear wacky,
Salam,

Here are some questions we ask when we're recruiting Unix sys admins. I thought they may be useful for people who are going for interviews or certifications.
I've bunched them in lots of 5 questions. Please do not post your answers here. Keep them to yourself and then compare them to the answers which I'll post in a couple of days time. Here goes :

1) What switches can you give to the ls command to sort the output in time-modified order?

# ls -lt

2) What does the script command do?

It will save all the work into a file, it will be good for assignments in Colleges & Universities.

3) I have a file called wacky.backup.tgz ,how would you extract the contents of this file?

# tar zxvf wacky.backup.tgz

4) How would you list the names of the files in /etc that contained the string 'hostname' ?

# ls /etc/*hostname*

5) Given a plain text file, how would you remove all the newline characters so that the whole file appeared as one long line?

# tr -d '\012' < file > newfile

or

# tr "\n" " " < file > newfile

or

# awk '{ str1=str1 $0 }END{ print str1 }'

Best Regards.