Commands tagged cat

the tee command does fine with file names, but not so much with file descriptors, such as &2 (stderr). This uses process redirection to tee to the specified descriptor.

In the sample output, it's being used to tee to stderr, which is connected with the terminal, and to wc -l, which is also outputting to the terminal. The result is the output of bash --version followed by the linecount

Replaces tabs in output with spaces. Uses perl since sed seems to work differently across platforms.

or

Most pagers like less, more, most, and others require additional processes to be loaded, additional cpu time used, and if that wasn't bad enough, most of them modify the output in ways that can be undesirable.

What I wanted was a "more" pager that was basically the same as running:

Without modifying the output and without additional processes being created, cpu used, etc. Normally if you want to scroll the output of cat file without modifying the output I would have to scroll back my terminal or screen buffer because less modifies the output.

After looking over many examples ranging from builtin cat functions created for csh, zsh, ksh, sh, and bash from the 80's, 90s, and more recent examples shipped with bash 4, and after much trial and error, I finally came up with something that satisifed my objective. It automatically adjusts to the size of your terminal window by using the LINES variable (or 80 lines if that is empty) so

This is a great function that will work as long as your shell works, so it will work just find if you are booted in single user mode and your /usr/bin directory is missing (where less and other pagers can be). Using builtins like this is fantastic and is comparable to how busybox works, as long as your shell works this will work.

One caveat/note: I always have access to a color terminal, and I always setup both the termcap and the terminfo packages for color terminals (and/or ncurses and slang), so for that reason I stuck the

command at the beginning of the function, so it only runs 1 time, and that causes the -- SHMore -- prompt to have a blue background and bright white text.

This is one of hundreds of functions I have in my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html">.bash_profile at http://www.askapache.com/">AskApache.com, but actually won't be included till the next update.

If you can improve this in any way at all please let me know, I would be very grateful! ( Like one thing I want is to be able to continue to the next screen by pressing any key instead of now having to press enter to continue)

the last person who posted used the most roundabout way to concatinate files, there's a reason there's a "conCATinate" command... Using this method, you also get to choose the order of the files, below another person just did *.txt > combined.txt which is fine but the order depends on the implementation of "cat" which is probably alphabetical order of filenames.

print the lines of a file in randomized order

If you're on a system that doesn't have nl, you can use cat -n.

on this way we can define the body too

The format is JJJJJ YR-MO-DA HH:MM:SS TT L DUT1 msADV UTC(NIST) OTM

and is explained more fully here: http://tf.nist.gov/service/acts.htm

It's not a big line, and it *may not* work for everybody, I guess it depends on the detail of access_log configuration in your httpd.conf. I use it as a prerotate command for logrotate in httpd section so it executes before access_log rotation, everyday at midnight.

Similar.

random(6) - random lines from a file or random numbers

The sort utility is well used, but sometimes you want a little chaos. This will randomize the lines of a text file.

BTW, on OS X there is no

option! There is also no

These are only in the newer GNU core...

This is also faster than the alternate of:

uuencode the file to appear as an attachment

This just reads in a local file and sends it via email. Works with text or binary. *Requires* local mail server.

Pipe any output to "grep ." and blank lines will not be printed.

Save the script as: sort_file

Usage: sort_file < sort_me.csv > out_file.csv

This script was originally posted by Admiral Beotch in LinuxQuestions.org on the Linux-Software forum.

I modified this script to make it more portable.

Files containing ascii art (e.g. with .nfo extension) are typically not correctly reproduced at the command line when using cat. With iconv one can easily write a wrapper to solve this:

Useful to detect number of tabs in an empty line, DOS newline (carriage return + newline).

A tool that can help you understand why your parsing is not working.

Be aware of using the --password argument as it will appear your password in plain text on the screen. You may use -p argument instead, it will prompt you to enter you password in hidden mode.

This command lets you see and scroll through all of the strings that are stored in the RAM at any given time. Press space bar to scroll through to see more pages (or use the arrow keys etc).

Sometimes if you don't save that file that you were working on or want to get back something you closed it can be found floating around in here!

The awk command only shows lines that are longer than 20 characters (to avoid seeing lots of junk that probably isn't "human readable").

If you want to dump the whole thing to a file replace the final '| less' with '> memorydump'. This is great for searching through many times (and with the added bonus that it doesn't overwrite any memory...).

Here's a neat example to show up conversations that were had in pidgin (will probably work after it has been closed)...

(depending on sudo settings it might be best to run

first to get to a # prompt)

Takes input from the connected terminal and dumps it to the specified file. Stop writing and close file with control + D or the end of line character. Useful for copying+pasting large blobs of text over SSH to a new machine.