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.
here refers to the special device where your partitions are.
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).
indicates to which directory you want the partition to be available as.
Please note that mount command requires root privileges, so run the command as sudo ie,
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
(i) For GZipped files(.tar.gz extension)
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
Then untar using the command
Eg: If the archive is some-file.tar.bz2 then first unzip it using
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
(i) Installing new packages
(ii) Upgrade existing packages
(iii) Removing existing packages
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
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.