Commands using read (340)

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands


Check These Out

Find the package that installed a command

Turn white color to transparent for a series of png images
mogrify can be used like convert. The difference is that mogrify overwrites files: http://www.imagemagick.org/www/mogrify.html Of course, other source colors can be used as well.

quickly change all .html extensions on files in folder to .htm

Command to logout all the users in one command
Only to logout all users except root

List latest 5 modified files recursively
The output format is given by the -printf parameter: %T@ = modify time in seconds since Jan. 1, 1970, 00:00 GMT, with fractional part. Mandatory, hidden in the end. %TY-%Tm-%Td %TH:%TM:%.2TS = modify time as YYYY-MM-DD HH:MM:SS. Optional. %p = file path Refer to http://linux.die.net/man/1/find for more about -printf formatting. ------------------------ sort -nr = sort numerically and reverse (higher values - most recent timestamp - first) head -n 5 = get only 5 first lines (change 5 to whatever you want) cut -f2- -d" " = trim first field (timestamp, used only for sorting) ------------------------ Very useful for building scripts for detecting malicious files upload and malware injections.

Create a bunch of dummy files for testing
Sometimes I need to create a directory of files to operate on to test out some commandlinefu I am cooking up. The main thing is the range ({1..N}) expansion.

See the 10 programs the most used

Backticks are evil
This is a simple example of using proper command nesting using $() over ``. There are a number of advantages of $() over backticks. First, they can be easily nested without escapes: $ program1 $(program2 $(program3 $(program4))) versus $ program1 `program2 \`program3 \`program4\`\`` Second, they're easier to read, then trying to decipher the difference between the backtick and the singlequote: `'. The only drawback $() suffers from is lack of total portability. If your script must be portable to the archaic Bourne shell, or old versions of the C-shell or Korn shell, then backticks are appropriate, otherwise, we should all get into the habit of $(). Your future script maintainers will thank you for producing cleaner code.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

python smtp server
This command will start a simple SMTP server listening on port 1025 of localhost. This server simply prints to standard output all email headers and the email body.


Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: