Commands by jaymzcd (4)

  • Make directories for and mount all iso files in a folder

    Show Sample Output


    2
    for file in *.iso; do mkdir `basename $file | awk -F. '{print $1}'`; sudo mount -t iso9660 -o loop $file `basename $file | awk -F. '{print $1}'`; done
    jaymzcd · 2009-10-17 20:07:31 4
  • Join a folder full of split files

    If you use newsgroups then you'll have come across split files before. Joining together a whole batch of them can be a pain so this will do the whole folder in one. Show Sample Output


    2
    for file in *.001; do NAME=`echo $file | cut -d. -f1,2`; cat "$NAME."[0-9][0-9][0-9] > "$NAME"; done
    jaymzcd · 2009-07-29 10:04:26 8
  • Print summary of referers with X amount of occurances

    This prints a summary of your referers from your logs as long as they occurred a certain number of times (in this case 500). The grep command excludes the terms, I add this in to remove results Im not interested in. Show Sample Output


    1
    awk -F\" '{print $4}' *.log | grep -v "eviljaymz\|\-" | sort | uniq -c | awk -F\ '{ if($1>500) print $1,$2;}' | sort -n
    jaymzcd · 2009-05-05 22:21:04 4
  • Count how many times a certain referer appears in your apache log

    I use this (well I normally just drop the F=*.log bit and put that straight into the awk command) to count how many times I get referred from another site. I know its rough, its to give me an idea where any posts I make are ending up. The reason I do the Q="query" bit is because I often want to check another domain quickly and its quick to use CTRL+A to jump to the start and then CTRL+F to move forward the 3 steps to change the grep query. (I find this easier than moving backwards because if you group a lot of domains with the pipe your command line can get quite messy so its normally easier to have it all at the front so you just have to edit it & hit enter). For people new to the shell it does the following. The Q and F equals bits just make names we can refer to. The awk -F\" '{print $4}' $F reads the file specified by $F and splits it up using double-quotes. It prints out the fourth column for egrep to work on. The 4th column in the log is the referer domain. egrep then matches our query against this list from awk. Finally wc -l gives us the total number of lines (i.e. matches). Show Sample Output


    0
    Q="reddit|digg"; F=*.log; awk -F\" '{print $4}' $F | egrep $Q | wc -l
    jaymzcd · 2009-05-05 21:51:16 6

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands

Check These Out

Using numsum to sum a column of numbers.
numsum is part of of the num-utils package, which is available in some Linux distros and can also be downloaded at http://suso.suso.org/xulu/Num-utils. It contains about 10 different programs for dealing with numbers from the command line. Obviously you can do a lot of things that the num-utils programs do in awk, sed, bash, perl scripts, but num-utils are there so that you don't have to remember the syntax for more complex operations and can just think: compute the sum, average, boundary numbers, etc.

Tells the shell you are using

List all groups and the user names that were in each group
"cut" the user names from /etc/passwd and then running a loop over them.

A command to copy mysql tables from a remote host to current host via ssh.
In the example above 3 tables are copied. You can change the number of tables. You should be able to come up with variants of the command by modifying the mysqldump part easily, to copy some part of remote mysql DB.

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Find which service was used by which port number

Detect illegal access to kernel space, potentially useful for Meltdown detection
Based on capsule8 agent examples, not rigorously tested

Have a smile
Outputs utf-8 smileys

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: