March 13, 2010
Attach words horizontally using shell scripting
Linux General,To paste contents of two files horizontally, paste command can be used. Create a file called cmd with the following content: # cat cmd /usr/sbin/useradd /usr/sbin/useradd /usr/sbin/useradd Create another file called newusers # cat newusers tom dick harry Now run the following command # paste -d ” ” cmds newusers > add.sh The -d ”…
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March 13, 2010
Find empty files in Linux
Linux General,find command provides two options to detect empty files $ find . -size 0c or $ find . -empty To find and delete all the empty files under the current directory at one go $ find . empty -exec rm -f {} \; To find and delete all empty directories under the current directory $…
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March 13, 2010
Capture top command output in a file
Linux General,Capture top command output in a file The output of top command can be captured as follows top -b -n1 > /tmp/top1.txt This will run top command once and write the output to a file, then exit. To run top 3 times with an interval of 5 seconds, run the following command top -b -n3…
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January 29, 2010
Difference between grep and egrep
Linux General,Difference between grep and egrep egrep is extended grep which includes additional regular expression metacharacters like ?, +, () and | Eg: egrep “(People|sense)” values.txt This command searches for patterns People and sense in file values.txt
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January 1, 2010
Create directory & set permission using a single Linux command
Linux General,Linux/Windows Support,Generaly, we create directory using “mkdir” command and then change it’s permissions using “chmod” command. Create directory & set permission using a single Linux command Actually, we can set the permissions for the directory at the time of it’s creation itself, with the following command: $ mkdir zyz -v -m 644 mkdir: created directory `zyz'…
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January 1, 2010
Linux Package Management Tips
Linux General,Linux/Windows Support,Try these Linux package management tips. Linux Package Management Tips 1) To check if a package is available in repositories and if so available, to check the version and size of the package, as superuser run the following commands in respective distro: Fedora, CentOS: yum list <package_name> Ubuntu/Debian: aptitude search <package_name> OpenSuse: zypper search <package_name>…
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January 1, 2010
Find programs hogging bandwidth using iftop command in Linux
Linux General,Linux/Windows Support,Find programs hogging bandwidth using iftop command in Linux Using iftop command we shall be able to determine what program is hogging bandwidth. iftop -bNBP is the commonly used option where -n don’t do hostname lookups -N don’t convert port numbers to services -B Display bandwidth in bytes -P show ports as well as hosts…
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December 26, 2009
Linux modules and libraries
Linux General,Dynamically linked libraries are linked and loaded at run time, either by “ld.so” or “ld-linux.so”, depending on how it was compiled: in a.out or ELF format. Every program whenever they need a library, look through a known list of places to find the needed library. One place they look is “/etc/ld.so.cache”, which contains an ordered…
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December 26, 2009
RPM – RedHat Package Manager
Linux General,What does a RPM Package contain? RPMs (*.rpm) typically include 1) the compiled programs and/or libraries needed for the package, 2) documentation 3) install, verify, and uninstall scripts 4) cryptographic signatures for each file in the package. This makes it easy to verify the integrity of the package. 5) It also includes a list of…
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September 16, 2009
Linux Security Tools
Linux General,In this page i will try to provide some of the must have tools for linux OS. Some of these tools can also be used for FreeBsd: ROOT KIT HUNTERS: Installation how to * CHKROOTKIT * RKHUNTER * ROOTCHECK @RootCheck: You can download the rootcheck latest version from the following URL: http://www.ossec.net/rootcheck/files/ Installation how to:…
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