Commands tagged bash

Run the alias command, then issue

and resize your terminal window (putty/console/hyperterm/xterm/etc) then issue the same command and you'll understand.

Insructs the shell that if LINES is not set or null to use the output from `tput lines` ( ncurses based terminal access ) to get the number of lines in your terminal. But furthermore, in case that doesn't work either, it will default to using the default of 80.

The default for TAIL is to output the last 10 lines, this alias changes the default to output the last x lines instead, where x is the number of lines currently displayed on your terminal - 7. The -7 is there so that the top line displayed is the command you ran that used TAIL, ie the prompt.

Depending on whether your PS1 and/or PROMPT_COMMAND output more than 1 line (mine is 3) you will want to increase from -2. So with my prompt being the following, I need -7, or - 5 if I only want to display the commandline at the top. ( http://www.askapache.com/linux/bash-power-prompt.html )

275MB/748MB

[7995:7993 - 0:186] 06:26:49 Thu Apr 08 [askapache@n1-backbone5:/dev/pts/0 +1] ~

In most shells the LINES variable is created automatically at login and updated when the terminal is resized (28 linux, 23/20 others for SIGWINCH) to contain the number of vertical lines that can fit in your terminal window. Because the alias doesn't hard-code the current LINES but relys on the $LINES variable, this is a dynamic alias that will always work on a tty device.

Take a file and ,."()?!;: give a list of all the words in order of increasing length.

First of all use tr to map all alphabetic characters to lower case and also strip out any puntuation.

A-Z become a-z

,."()?!;: all become \n (newline)

I've ignored - (hyphen) and ' (apostrophe) because they occur in words.

Next use bash to print the length ${#w} and the word

Finally sort the list numerically (sort -n) and remove any duplicates (sort -u).

Note: sort -nu performs strangely on this list. It outputs one word per length.

Bash only, no sed, no awk. Multiple spaces/tabs if exists INSIDE the line will be preserved. Empty lines stay intact, except they will be cleaned from spaces and tabs if any available.

Says time every 5 seconds in hours, minutes and seconds using festival.

works the same, but uses festival instead of espeak

Just like "!$", except it does it instantly. Then you can hit enter if you want.

Don't do this:

Using a bash "here strings" and "here documents" look leeter than piping echo into the command. Also prevents subshell execution. Word is also expanded as usual.

Sometimes, you don't want to just replace the spaces in the current folder, but through the whole folder tree - such as your whole music collection, perhaps. Or maybe you want to do some other renaming operation throughout a tree - this command's useful for that, too.

To rename stuff through a whole directory tree, you might expect this to work:

for a in `find . -name '* *'`;do mv -i "$a" ${a// /_};done

No such luck. The "for" command will split its parameters on spaces unless the spaces are escaped, so given a file "foo bar", the above would not try to move the file "foo bar" to "foo_bar" but rather the file "foo" to "foo", and the file "bar" to "bar". Instead, find's -execdir and -depth arguments need to be used, to set a variable to the filename, and rename files within the directory before we rename the directory.

It has to be -execdir and won't work with just -exec - that would try to rename "foo bar/baz quux" to "foo_bar/baz_quux" in one step, rather than going into "foo bar/", changing "baz quux" to "baz_quux", then stepping out and changing "foo bar/" into "foo_bar/".

To rename just files, or just directories, you can put "-type f" or "-type d" after the "-depth" param.

You could probably safely replace the "mv" part of the line with a "rename" command, like rename 'y/ /_/' *, but I haven't tried, since that's way less portable.

Useful contexts :

You are doing yoga or some other physical training in which you are holding a position.

Or you practice the pomodoro productivity technique.

Or your girlfriend said "We're leaving in 40 minutes".

Design details:

sleep executes before espeak to give you a 5 seconds head start.

espeak is run in the background so it doesn't mess up the timing.

Applies each file operator using the built-in test.

/home/askapache/.sq

-a True - file exists.

-d True - file is a directory.

-e True - file exists.

-r True - file is readable by you.

-s True - file exists and is not empty.

-w True - the file is writable by you.

-x True - the file is executable by you.

-O True - the file is effectively owned by you.

-G True - the file is effectively owned by your group.

-N True - the file has been modified since it was last read.

Full Function:

testt ()

{

local dp;

until [ -z "${1:-}" ]; do

dp="$1";

[[ ! -a "$1" ]] && dp="$PWD/$dp";

command ls -w $((${COLUMNS:-80}-20)) -lA --color=tty -d "$dp";

[[ -d "$dp" ]] && find "$dp" -mount -depth -wholename "$dp" -printf '%.5m %10M %#15s %#9u %-9g %#5U %-5G %Am/%Ad/%AY %Cm/%Cd/%CY %Tm/%Td/%TY [%Y] %p\n' -a -quit 2> /dev/null;

for f in a b c d e f g h L k p r s S t u w x O G N;

do

test -$f "$dp" && help test | sed "/-$f F/!d" | sed -e 's#^[\t ]*-\([a-zA-Z]\{1\}\) F[A-Z]*[\t ]* True if#-\1 "'$dp'" #g';

done;

shift;

done

}

works in bash

Here is the full function (got trunctated), which is much better and works for multiple queries.

function cmdfu () {

local t=~/cmdfu;

until [[ -z $1 ]]; do

echo -e "\n# $1 {{{1" >> $t;

curl -s "commandlinefu.com/commands/matching/$1/`echo -n $1|base64`/plaintext" | sed '1,2d;s/^#.*/& {{{2/g' | tee -a $t > $t.c;

sed -i "s/^# $1 {/# $1 - `grep -c '^#' $t.c` {/" $t;

shift;

done;

vim -u /dev/null -c "set ft=sh fdm=marker fdl=1 noswf" -M $t;

rm $t $t.c

}

Searches commandlinefu for single/multiple queries and displays syntax-highlighted, folded, and numbered results in vim.

You need to have mtr installed on your host.

This command uses ping to get the routers' IP addresses to the destination host as traceroute does. If you know what I mean..

Try it this way...

Mac install ssh-copy-id

From there on out, you would upload keys to a server like this:

(make sure to double quote the full path to your key)

or, if your SSH server uses a different port (often, they will require that the port be '2222' or some other nonsense:

(note the double quotes on *both* the "/path/to/key" and "user@server -pXXXX"):

...where XXXX is the ssh port on that server

I have used single packet, and in a silent mode with no display of ping stats. This is with color and UI improvement to the http://www.commandlinefu.com/commands/view/10220/check-if-a-machine-is-online. It is as per the enhancements suggested.

or add this line to your ~/.vimrc if using vim

Writes out the shebang line (#!/bin/bash) to the script.

write first line `#!`

Delete range of lines. Ex: Line 6 through 66 in .

Delete a range of line