March 16, 2010
Extract the contents of an RPM
Linux General,Using rpm2cpio command, the contents of an RPM package can be extracted without having to install the package. For source RPMs too this command can be used. This is illustrated with an example as follows, where we extract the contents of RPM, google-chrome-beta_current_i386.rpm. $ rpm2cpio google-chrome-beta_current_i386.rpm | cpio -idv ./etc/cron.daily ./etc/cron.daily/google-chrome ./opt/google/chrome ./opt/google/chrome/chrome ./opt/google/chrome/chrome-sandbox ./opt/google/chrome/chrome.pak…
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March 13, 2010
Difference between Buffer and Cache
Linux General,Buffers are allocated by various processes to use as input queues, etc. Most of the time, buffers are some processes’ output, and they are file buffers. A simplistic explanation of buffers is that they allow processes to temporarily store input in memory until the process can deal with it. Difference between Buffer and Cache Cache…
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March 13, 2010
Memory Usage in Linux
Linux General,Check the memory usage on a linux system with the command given below. The free command helps in getting the memory usage in the system [rams@stopprepare-lx ~]$ free -m total...
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March 13, 2010
Disable the Error Beep in MySQL
Linux General,To temporarily disable the beep, pass –no-beep along when logging into the server: %>mysql -u root -p –no-beep To permanently disable this annoyance, add no-beep to the [client] section of your .my.cnf file.
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March 13, 2010
How FreeBSD identifies hard disks and drives
Linux General,FreeBSD identifies various types of hard disks and drives with following naming convention ad ATAPI (IDE) disk da SCSI direct access disk acd ATAPI (IDE) CDROM cd SCSI CDROM fd Floppy disk To know the hardware detected by the kernel at boot time refer the file /var/run/dmesg.boot or use the command dmesg. The various hard…
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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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