The Archives

  • 09.Jan.12
    Greping from inside Vim shell | fernape | (0)
    Hi there, First things first: Happy New Year! :) One task I usually perform when I am writing code is grepping the code for a certain string. In order to do that, I used to exit Vim (either with :q or suspending the process), grep the files and then go back to my Vim session. This approximation has one main drawback: I usually don't remember all the matches reported by grep. Vim provides a mechanism for invoking grep from a Vim session. The command is: :grep string files This way, one can invoke his local grep command and the results will be integrated into the ...
  • 22.Sep.11
    How to know if a CPU is 32 or 64-bit shell | rafacas | (0)
    Nowadays almost all the computers have a 64-bit CPU, but sometimes we are logged in on a remote server and do not know what kind of CPU it has and we need to know it to install a package or... out of mere curiosity. In those cases we can run the following command: $ grep --color lm /proc/cpuinfo flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss syscall nx rdtscp lm constant_tsc up ida nonstop_tsc arat pni ssse3 cx16 sse4_1 sse4_2 popcnt lahf_lm If the lm flag ...
  • 20.Apr.09
    Monitoring HTTP requests from the command line network | rafacas | (0)
    Some days ago Javisantana sent me a tweet with a link to a one-liner HTTP requests monitor. It goes as follows with some ouput added: $ sudo tcpdump -i en1 -n -s 0 -w - | grep -a -o -E "Host\: .*|GET \/.*" Password: tcpdump: listening on en1, link-type EN10MB (Ethernet), capture size 65535 bytes GET / HTTP/1.1 Host: GET / HTTP/1.1 Host: GET / HTTP/1.1 Host: GET / HTTP/1.1 Host: GET /intl/en_com/images/logo_plain.png HTTP/1.1 Host: [...] Replace en1 with your network interface's name. Usually enX in BSD-like OSes and ethX in Linux. You can create an alias named httpdump and add it to ~/.bash_profile: alias httpdump='sudo tcpdump -i en1 -n -s 0 -w ...
  • 17.Apr.09
    Showing a computer’s open ports cmd, network | rafacas | (0)
    $ netstat -an | grep -i listen Shows the open ports on all the IPs of the computer the command is run on.
  • 04.Mar.09
    Removing blank lines from a file shell | rafacas | (0)
    Sometimes I need to remove blank lines from a specific file. I usually do it with the two following commands: $ grep -v "^$" file or $ sed '/^$/d' file Obviously, if you want to save the output you should redirect it to another file, for example: $ sed '/^$/d' file1 > file2
  • 14.Feb.09
    Is your site up? scripts | rafacas | (0)
    When I cannot reach one of my sites, I do not know if it is my problem, my ISP's or my hosting provider's. This is why I use the service down for everyone or just me. I have written a simple script which uses that service. Its usage is: $ ./ is up and the script is: #!/bin/bash # # 2009 - Rafa Casado - numargs=$# if [ $numargs -ne 1 ] then echo "Usage: $0 domain" echo "Ex: $0" exit 1 fi DOMAIN=$1 IS_UP=`wget -nv -O ...
  • 02.Feb.09
    Currency conversion script scripts | rafacas | (1)
    In this time of crisis perhaps we need to pay more attention to financial issues. I am interested in converting some currencies so I have written a script that given two currencies, converts on to the other. The script searches the info on Google Finance's page. An example of its usage is: $ ./ EUR USD 1 EUR = 1.316 USD The available currencies are: EUR - Euros USD - United State Dollar GBP - British Pound JPY - Japanese Yen CHF - Swiss Franc CAD - Canadian Dollar AUD - Australian Dollar INR - Indian ...
  • 02.Dec.08
    Quiet grep automated, shell | pfortuny | (0)
    Usually during an cron job, one needs to check for an expression in a log file, or in the output of a command, without generating any cumbersone new output (such as a standard grep would do): this is exactly the use of the -q option of grep. For example: for i in `grep -v '^#' /etc/passwd | cut -f1 -d:` grep $i /var/log/samba/log.smbd | grep -q 'failed to authenticate' if [ $? == 0 ] ; then mail -s 'Error in samba' $i <<EOM ...
  • 25.Oct.08
    Recursive grep in Solaris cmd | rafacas | (1)
    $ find . | xargs grep PATTERN In Solaris, the grep command does not have the -R (-r, --recursive) option which reads all files under each directory, recursively. The above command can be used to do the same in Solaris.
  • 01.Jul.08
    Time of last system shutdown cmd | rafacas | (0)
    $ last -x | grep shutdown | head -1 shutdown system down 2.6.24-16 Tue Jun 24 13:31 - 15:08 (01:37) This command displays the time of the last system shutdown.