gnuServices

Linus Tips

• Date Command
• vi editor help
• vi/Vim recording actions
• File permissions, groups and access control
• What is ssh ?
• ssh without password
• Finding files and executing commands on them
• Finding and Listing files
• Plotting with gnuplot
• Sharing files with Sambaserver
• Linking files with ln
• Lynx tricks
• Automatic login with ftp
• Sharing internet connection over a LAN
• What is a Firewall ?
• ssh works scp doesn't ?
• Command line editing and bash
• Calendar command
• Touching files
• Kill all zombie processes
• Count number of files (and directories) in working directory
• Useful ls
• Find files in working directory which were modified in last two days
• aliases
• Removing duplicate lines from a file
• Refering to dictionary
• Cut Command
• Rename Command

 Date Command

 Touching files

Try the following command to see what it does!
touch {x,y}{x,y}{x,y}

 Kill all zombie processes

ps -ef | grep "defunct" | cut -f1 | xargs kill
xargs is used to pass every line as argument to the command following it

More on cut..

 Count number of files (and directories) in working directory.

ls | wc -l

 Useful ls

ls -t
list files in reverse order of the modification time

ls -lat
all files and full listing; can be piped to more or less if list is big

ls -i
see inodes

ls --color
gives colored listing. You can alias ls for 'ls --color' in your .bashrc (or some other like .cshrc) file in the following way.

alias ls='ls --color'

 aliases

cp='cp -i'

ls='ls --color'

 Removing duplicate lines from a file

sort filename1 | uniq > filename2

Sort and remove duplicate lines from filename1 and create filename2

 Refering to dictionary

look word

word can be initial letters of the word(s) you are looking for
look extra shows all the words starting with extra

 Cut Command - Following is an example of how cut command can be used.

If you have a data-file with "|" as the separator, you can output only some of the fields with this command.

cut -d "|" -f1,4,5 filename

This will output only the first, fourth and the fifth fields from the file. -d option is used to specify the delimiter.

 rename command

If you have files with extension .JPG and you want to change it to lowercase .jpg.
rename .JPG .jpg *.JPG

Lynx traversal creates .dat files starting with lnk. If you want to rename all these file so that all start with some other letters you can do it with rename.
rename lnk abcd *.dat