Some Basic Linux Commands

catSends file contents to standard output. This is a way to list the contents of short files to the screen. It works well with piping.
cat .bashrcSends the contents of the “.bashrc” file to the screen.
cdChange directory
cd /homeChange the current working directory to /home. The ‘/’ indicates relative to root, and no matter what directory you are in when you execute this command, the directory will be changed to “/home”.
cd httpdChange the current working directory to httpd, relative to the current location which is “/home”. The full path of the new working directory is “/home/httpd”.
cd ..Move to the parent directory of the current directory. This command will make the current working directory “/home.
cd ~Move to the user’s home directory which is “/home/username”. The ‘~’ indicates the users home directory.
cpCopy files
cp myfile yourfileCopy the files “myfile” to the file “yourfile” in the current working directory. This command will create the file “yourfile” if it doesn’t exist. It will normally overwrite it without warning if it exists.
cp -i myfile yourfileWith the “-i” option, if the file “yourfile” exists, you will be prompted before it is overwritten.
cp -i /data/myfile .Copy the file “/data/myfile” to the current working directory and name it “myfile”. Prompt before overwriting the file.
cp -dpr srcdir destdirCopy all files from the directory “srcdir” to the directory “destdir” preserving links (-p option), file attributes (-p option), and copy recursively (-r option). With these options, a directory and all it contents can be copied to another directory.
dddd if=/dev/hdb1 of=/backup/Disk duplicate. The man page says this command is to “Convert and copy a file”, but although used by more advanced users, it can be a very handy command. The “if” means input file, “of” means output file.
dfShow the amount of disk space used on each mounted filesystem.
lessless textfileSimilar to the more command, but the user can page up and down through the file. The example displays the contents of textfile.
lnCreates a symbolic link to a file.
ln -s test symlinkCreates a symbolic link named symlink that points to the file test Typing “ls -i test symlink” will show the two files are different with different inodes. Typing “ls -l test symlink” will show that symlink points to the file test.
locateA fast database driven file locator.
slocate -uThis command builds the slocate database. It will take several minutes to complete this command. This command must be used before searching for files, however cron runs this command periodically on most systems.
locate whereisLists all files whose names contain the string “whereis”.
logoutLogs the current user off the system.
lsList files
lsList files in the current working directory except those starting with . and only show the file name.
ls -alList all files in the current working directory in long listing format showing permissions, ownership, size, and time and date stamp
moreAllows file contents or piped output to be sent to the screen one page at a time.
more /etc/profileLists the contents of the “/etc/profile” file to the screen one page at a time.
ls -al |morePerforms a directory listing of all files and pipes the output of the listing through more. If the directory listing is longer than a page, it will be listed one page at a time.
mvMove or rename files
mv -i myfile yourfileMove the file from “myfile” to “yourfile”. This effectively changes the name of “myfile” to “yourfile”.
mv -i /data/myfile .Move the file from “myfile” from the directory “/data” to the current working directory.
pwdShow the name of the current working directory
more /etc/profileLists the contents of the “/etc/profile” file to the screen one page at a time.
shutdownShuts the system down.
shutdown -h nowShuts the system down to halt immediately.
shutdown -r nowShuts the system down immediately and the system reboots.
whereisShow where the binary, source and manual page files are for a command
whereis lsLocates binaries and manual pages for the ls command.

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