Although Linux had progressed far from being a command-line only OS to a full fledged totally GUI based one, sometimes, the command line is the best way to get something done. Here are 5 of the must-know commands. These commands can b quite useful and handy.
1: mount: Used for mounting Windows/Other partitions, just in case it isn’t automatically mounted.
Usage:
mount
here
Rather than referring to partitions as drive letters as Windows, every partition in Linux is indicated by a special device. For eg in case if IDE(parallel ATA drives) the Primary master will be /dev/hda and the primary partition will be /dev/hda1(Windows C:) and the logical partitions will be /dev/hda5, /dev/hda6 and so on(for Windows D:, E:.. so on).
Please note that mount command requires root privileges, so run the command as sudo ie,
sudo mount
Eg: If you wish to mount the Windows C partition to a /windows/C the command will be,sudo mount /dev/hda1 /windows/C
For SATA drives, the “hdx” will be replaced by “sdx” ie, instead of /dev/hda1
it’ll be /dev/sda1
2: tar/bzip2/bunzip2: For extracting archives, this command is useful for extracting to directories other than the home directory, where root privileges are required
Usage:
(i) For GZipped files(.tar.gz extension)
tar xvfz
Eg: If the archive name is some-file.tar.gz, then the command will be
tar xvfz some-file.tar.gz
(ii)For Bzipped files (.tar.bz2 extension)
First, unzip the archive using
bunzip2
Then untar using the command
tar xvf
Eg: If the archive is some-file.tar.bz2 then first unzip it using
bunzip some-file.tar.bz2
You’ll get the file some-file.tar. Next untar it using
tar xvf some-file.tar
- rpm/dpkg - Install/Upgrade/Remove RPM/Debian Packages
Usage:
(i) Installing new packages
rpm -ivh <package-name.rpm>
dpkg -i <package-name.deb>
(ii) Upgrade existing packages
rpm -Uvh <package-name.rpm>
dpkg -i <package-name.deb>
(iii) Removing existing packages
rpm -e
dpkg -r
Note that these commands are suited for individual commands, whose dependencies are met. For complex packages, having many dependencies it’s better to use apt-get/smart.
For smart: smart install
For apt-get: apt-get install
Again these commands require root privileges, so prefix sudo before each of these commands.
- cat - Concatenate files and print on the standard output. Useful for viewing short text files, logs without having to open any editors
Usage:
cat /path/to/file
Eg: cat /var/log/syslog
If the text file is lengthy, pipe it via more to scroll ie
cat /path/to/file |more
Eg: cat /var/log/syslog |more
- dmesg - The program helps users to print out their bootup messages. Instead of copying the messages by hand, the user need only:
dmesg > boot.messages
and mail the boot.messages file to whoever can debug their problem.
dmesg |tail Outputs only the last part of dmesg, and is useful to identify any errors, which occured, say if a removable drive is inserted.
