The value for the sort command's -k argument is the column in the CSV file to sort on. In this example, it sorts on the second column. You must use some form of the sort command in order for uniq to work properly.

Concatenate the stdout of multiple commands. Show Sample Output

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xclip -o > /tmp/spell.tmp # Copy clipboard contents to a temp file aspell check /tmp/spell.tmp # Run aspell on that file cat /tmp/spell.tmp | xclip # Copy the results back to the clipboard, so that you can paste the corrected text I'm not sure xclip is installed in most distributions. If not, you can install x11-apps package

Good old cat & output redirection. Using this method you can combine all kinds of things - even mpeg files. My video camera makes a series of .mpeg files that are broken into 4gb chunks. Using this command I can easily join them together. Even better, combined with the cp command the files can be copied and joined in one step.

To sort hidden files first, simply switch the two inner `ls` commands. I have this aliased to `dira` `dir` is aliased to the simpler version with no hidden files: ls -l --color=always | less -R

A common mistake in Bash is to write command-line where there's command a reading a file and whose result is redirected to that file. It can be easily avoided because of : 1) warnings "-bash: file.txt: cannot overwrite existing file" 2) options (often "-i") that let the command directly modify the file but I like to have that small function that does the trick by waiting for the first command to end before trying to write into the file. Lots of things could probably done in a better way, if you know one... Show Sample Output

If you use newsgroups then you'll have come across split files before. Joining together a whole batch of them can be a pain so this will do the whole folder in one. Show Sample Output

This will diff your local version of the file with the latest version in svn. I put this in a shell function like so: svd() { vimdiff <(svn cat "$1") "$1"; }

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

If the connection works you should see a "hello" on host A. If not: check your cabeling etc :-)

This is a cool trick to view the contents of the file on /dev/pts/0 (or whatever terminal you're using), and also send the contents of that file to another program by way of an unnamed pipe. All the while, you've not bothered saving any extra data to disk, like you might be tempted to do with sed or grep to filter output.

Get a list of all the unique hostnames from the apache configuration files. Handy to see what sites are running on a server. A slightly shorter version.

Same as original, but works in bash

In my case it was actually like this... Show Sample Output

This can be taken from the pdftk docs http://www.pdflabs.com/docs/pdftk-man-page/ http://www.pdflabs.com/docs/pdftk-cli-examples/ , but the command examples are not simple. Show Sample Output

This uses some tricks I found while reading the bash man page to enumerate and display all the current environment variables, including those not listed by the 'env' command which according to the bash docs are more for internal use by BASH. The main trick is the way bash will list all environment variable names when performing expansion on ${!A*}. Then the eval builtin makes it work in a loop. I created a function for this and use it instead of env. (by aliasing env). This is the function that given any parameters lists the variables that start with it. So 'aae B' would list all env variables starting wit B. And 'aae {A..Z} {a..z}' would list all variables starting with any letter of the alphabet. And 'aae TERM' would list all variables starting with TERM. aae(){ local __a __i __z;for __a in "$@";do __z=\${!${__a}*};for __i in `eval echo "${__z}"`;do echo -e "$__i: ${!__i}";done;done; } And my printenv replacement is: alias env='aae {A..Z} {a..z} "_"|sort|cat -v 2>&1 | sed "s/\\^\\[/\\\\033/g"' From: http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html Show Sample Output

Working with log files that contains variable length messages wrapped between open and close tags it may be useful to filter the messages upon a keyword. This works fine with GNU sed version 4.2 or higher, so pay attention to some unix distros (solaris, hp-ux, etc.). Linux should be ok. Show Sample Output

Pipe | avoid escaping occurences problems in using sed and make it easier to use

This should probably only be used for testing in a dev environment as it's not terribly efficient, but if you're doing something that might trash a DB and you still want the old data available, this works like a charm.