Bash Tips

2006-11-29T17:29:01Z

86.140.1.253: /* Sous MC */

==Documentation==
* [http://ldp.unixtech.be/LDP/abs/html/index.html Advanced Bash-Scripting Guide]
* http://www.ss64.com/bash/index.html
* http://tille.xalasys.com/training/bash

==Sous MC==

* Pour pouvoir faire des sélections à la souris (gpm ou X) sans que mc ne les interprète, tenir la touche shift enfoncée
* J'aime lancer mes mc root avec un alias qui me met un fond rouge plutot que bleu, l'idée vient de Damn Small Linux mais ici en employant les options mc:
alias smc='sudo -H mc --colors normal=,red:selected=,brightmagenta:marked=,red:markselect=,brightmagenta:directory=,red:executable=,red:link=,red:stalelink=brightcyan,red:device=,red:special=,red:core=,red:input=,green /root'
* ctrl+o: toggler l'affichage console/mc
* alt+o: meme pwd dans l'autre fenetre
* alt+enter: copie sur la ligne de commande la ou le curseur se trouve
* *: inverse la selection
* +: permet de selectionner selon un filtre (+ et enter prend directement tout ce qui se trouve dans le repertoire courant)
* -: permet de deselectionner avec un filtre
* ctrl+u: undo
* mc permet d'ouvrir directement un ftp, d'ouvrir les targz, les rpm, les deb, les iso, ... en fait tout ce qui possède une système de fichiers

* Si il y a un probleme avec la touche alt (qui ne fonctionne pas en tant que touche "meta"): options -> display bits -> 3eme: uncheck le 8-bits

==Séquences de couleur ISO 6429 (ANSI)==
echo -e "Test \033[31mrouge\033[m"
echo -e "Test \033[1;31mrouge vif\033[m"
echo -e "Test \033[32mvert\033[m"
echo -e "Test \033[1;31mvert vif\033[m"
man dir_colors

ESC[rowsA Cursor up
ESC[rowsB Cursor down
ESC[colsC Cursor right
ESC[colsD Cursor left
ESC[row;colH Set cursor position (top left is row 1, column 1)
ESC[2J Clear screen
ESC[K Clear from cursor to end of line
ESC[row;colf Set cursor position, same as "H" command
ESC[=modeh Set display mode; see table of mode values below
ESC[=model Set display mode; see table of mode values below
ESC[attr;attr;..m Set display attributes; see table of attribute values below
ESC[key;string;..p Substitute "string" for the specified key; see key substitutions section below.
ESC[s Save cursor position (may not be nested)
ESC[u Restore cursor position after a save
===Attribute Description===
*0 All attributes off (normal white on black)
*1 High intensity (bold)
*2 Normal intensity
*4 Underline (usually effective only on monochrome displays)
*5 Blinking
*7 Reverse Video
*8 Invisible
*30-37 Set the foreground color: 30=Black 31=Red 32=Green 33=Yellow 34=Blue 35=Magenta 36=Cyan 37=White
*40-47 Set the background color: 40=Black 41=Red 42=Green 43=Yellow 44=Blue 45=Magenta 46=Cyan 47=White
Settings are cumulative, so (for example) to set bright red foreground set all attributes off, then set red, then bold: echo _[0;31;1m.
===Display Modes===
*0 Text 40x25 monochrome
*1 Text 40x25 color
*2 Text 80x25 monochrome
*3 Text 80x25 color
*4 Graphics 320x200 4-color
*5 Graphics 320x200 4-color
*6 Graphics 640x200 2-color
*7 (cursor wrap kludge)
Mode 7 is an unfortunate kludge; Setting mode 7 with an "h" command tells ANSI to wrap text to the next line when it passes the end of a line; setting mode 7 with an "l" (lower-case L) command tells ANSI not to wrap text. For all other modes the "h" and "l" commands are equivalent.
===Key Substitutions===
The key substitutions ("p") command causes ANSI to substitute the text in "string" when the specified key is pressed. The key code can be a single character in quotes, a numeric ASCII value, or an extended code for a non ASCII key (e.g. function or cursor keys) in the form 0;n, where n is the scan code for the key. The string to be substituted can be a single character or character string in quotes, a numeric ASCII value, or an extended key code.
 For a list of numeric ASCII values, see ASCII Tables. For a list of extended key codes see Key Code and Scan Code Tables.
 To clear a key substitution, "substitute" the original key for itself.

==TAB completion==
* Avoid the bell: add "set bell-style visible" to ~/.inputrc (versus audible and none)
* Discover the rules when completing a given command, e.g. acroread: complete|grep acroread
 Rules are in /etc/bash_completion and loaded in the environment (see set)
* See http://aplawrence.com/Unix/customtab.html
** Enabling custom completions: shopt -s progcomp
** Registering a custom function to complete command line of e.g. myprog: complete -F _myprog -o dirnames myprog
** Creating the custom function:
_myprog()
{
local curw
COMPREPLY=()
curw=${COMP_WORDS[COMP_CWORD]}
COMPREPLY=($(compgen -A user -- $curw))
return 0
}

==Misc==

Pay attention when using '''sudo''' that $HOME is still configured as yours and you could end up with some user config files owned by root in your own directory.
 To avoid that, use "sudo -H" or to make it definitive, use visudo to add to the sudo conf: "Defaults always_set_home"

To convert ASCII Mac file to Unix file:
for file in *; do cat "$file" | tr \\15 \\12 >e;mv e "$file"; done

To convert a filename from uppercase to lowercase
for file in * ; do mv "$file" "$(echo -n $file|tr [[A-Z] [[a-z])" ; done

Boot Disk :
mkbootdisk numero version : voir version dans /lib/modules/2....
ou rdev -h : aide
rdev /boot/kernel - < nom du noyau
dd if=/boot/linux of=/dev/fd0 bs=8192

Conversion Ext2 -> Ext3

tune2fs -j /dev/hdXX
And don't forget to adapt fstab entry

===Devinette===

What is the output of this command?
<verbatim>
echo one>/tmp/t;(echo two>/dev/stdout)>>/tmp/t;cat /tmp/t
</verbatim>

Now, try...
 Astonishing, isn't it?!
 PS: to get what you expected, try >>/dev/stdout

Apparently when the command is executed, the sub-process is launched with /dev/stdout pointing to its /proc/self/fd/1 but this one is now set to /tmp/t so the sub-shell re-opens the file and overwrites it!

Note that under cygwin/bash, there is no real /dev/stdout and the result is one two

echo one>/tmp/t;m=$(echo two>/dev/stdout);echo $m>>/tmp/t;cat /tmp/t
is working as expected, /proc/self/fd/1 of the sub-process is now a pipe to the main process.

So a program is able to detect if its output was redirected or not!

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Bash Tips