SysadmandineOne day, sysadmins will rule the world…

Here’s my linux favourite commands, by type :

Scripting
1. egrep : aaah… if I had to keep only one, this would be the one I’d choose… can’t spend 10 minutes without using it.
2. sed : because I always need to replace something by something else 10 times on each line in huge files
3. xargs : helps me avoid the for loop, shorter to write, easier to remember and understand when you find it in history
4. awk : for me the most difficult one to use, but I so know that it can do just what I want that I always take the time.

System
5. kill : ha ha, makes me feel I’m powerful
6. ps fauxww : makes me think I can watch everything that’s happening in real time. Like watching 10 movies at the same time.
7. aptitude : I like his way of telling me everything of what he’s doing… so chatty !
8. dstat : this one is really good : tells me a lot of things and with colors, I think he just knows what I’m looking for each time I call him.

Network
9. ssh : is it necessary to say something about it? without him I’d be nothing.
10. telnet : I like the raw output, no interpretation, he’s stupid and this is sometimes really appreciable
11. host : simple tool for so great usefulness, even the basic usage is perfect
12. nmap : I looove knowing everything about hosts I can’t access…
13. tcpdump : really useful when you really dont understand what’s happening.
14. netstat : nmap from the inside. Feels like a treasure hunt sometimes.
15. mtr : seems just easy and fast, but also gives a lot of interesting information.

Tools
16. vim : makes me save so much time
17. screen : How did they live before screen? And I use only a small amount of its potential…

Storage
18. fdisk : boring in the begenning, fun once you know it by heart
19. sfdisk : really handy to mirror a disk partitionning scheme
20. mdadm : I love mdadm. Just love it, don’t know why.

Today I struggled with the time command.

I wanted to use it in a bash script, so I checked the man page, where I found interesting stuff :

Ok great. So I wrote my command like this :

hm. Maybe I did something wrong. Let’s try the man page’s example to understand how things work :

wtf??! The example given didn’t work either !
And then

ok… so, searching a little bit further helped me find the explanation :

Your shell (apparently bash) provides a builtin time function. If you want to use time binary, call it by absolute path (/usr/bin/time)

let’s try :

Finally! It was just a silly thing…

Just remember, when using the bash time, get the time in minutes/seconds:

and in seconds only :

:D

Today I learnt a new command :D

Ok I’m a little bit lying : I knew it before but I was using it only to put several lines into one unique line, like this :

Now, thanks to the new guy in front of me (the colorblind one), I will be able to replace a lot of “for” and ` ` by xargs :D

Some interesting uses of xargs :

Display the content af the current directory in 8 colums

Seems to be more efficient than “find /path -exec rm {} \;”, because xargs splits this list into sublists and calls rm once for every sublist, while find calls rm once for every single file.

to get uptime of each server in server.list