Linux:shell:Bash: How to change color of your shell printout

You could use 'echo -e' to change your printout text and background color by some color variables. One of the easiest ways to use them is to define shell variable, for example, define those variables in your shell script:

red='\e[0;31m'
RED='\e[1;31m'
blue='\e[0;34m'
BLUE='\e[1;34m'
cyan='\e[0;36m'
CYAN='\e[1;36m'
NC='\e[0m' # No Color

. '\e[0;36m': 0's place is the color of background (0, no effect, 1, bold, 4, underline) and 36 is the text color. You also can change background colors due to color values in the color table. For example, '\e[41;34m' changes background color to red and text color to blue.

How to print?

echo -e "$red These texts are in red$NC" #you must use '-e' to enable interpretation of the backslash-escaped characters, see echo's help.

or if you want to use it in 'printf':

printf "%s\n" "`echo -e $red`These texts are in red`echo -e $NC`"

There is a table of color values attached (this table is from the link). You can find color values what you want.

linux:shell: /bin/tar: Argument list too long

When you create a tar archive and have an error: /bin/tar: Argument list too long, then you could try an argument of tar:

-T or --files-from=F

(which allows you to get names to extract or create from file F).

linux:shell: broken 'while' loop

When I do a while loop in which there is a command 'ssh', the while loop just goes only one iteration and quits. The problem is from 'ssh' read stdin so that 'while' cannot read anymore and stop afterwards, for example,

while read CompName
do
ssh $CompName 'ls'
echo "Done"
done <>

In the example, only one iteration is conducted (including the echo line). The solutions are provided by google searching. One is general one, I think. 1) Redirect ssh stdin by

< /dev/null ssh $CompName 'ls'

2) ssh-specified trick: use '-n':

ssh -n $CompName 'ls'

linux:shell:bash:grep: multi-grep

If I want to search multi words by grep, I could do in the way:

egrep "a|b|c|d" my_input_file.txt

then egrep will help you to search OR of a, b, c and d. If searching for AND of multi-words, you can do by pipe:

grep a my_input_file.txt |grep b |grep c |grep d

. However, sometimes, it is not so easy to use pipe in one line for the above usage. You can always build string of the command first and evaluate it. For example,

cmd="grep $var1 my_input_file.txt|grep $var2"
...
cmd="$cmd |grep $var3"
...
eval $cmd

Linux:shell: awk: multiple separators

'awk' is a very useful shell command (also a program language) in linux (unix). You split one text line by it. For example, for the line

line="aa, b c , d , f "

what you can do in shell command (bash) is

echo $line|awk -F "," '{print $1 $2 $3 $4}' # to get different columns separated by ","

However, if you wanna split one line with multi-separators, then you could do in the way, for example,

$ line="aa, bb_ ccd: ee"
$ echo $line |awk -F ",|_|:" '{print $1$2$3}'

Note here "|" will do logic "OR" of all separators. This is similar 'egrep'. If you want to grep multi key words, then you could do in the same way (which has been addressed in my other blog, just search grep ).

Latex: subfigure: how to get rid of 'counter' of subcaption

The subfigure 's tutorial

If you want to get rid of 'counter' in front of your sub-captions, use to redefine the command: \thesubfigure by:

\renewcommand*{\thesubfigure}{}

(originally one in subfigure.sty is

\renewcommand*{\thesubfigure}{(\alph{subfigure})}

)

Linux:command: du and quota

My disk quota is full on my account at Fermilab (.../home/zhiyil/desktop/...). So I have to clean to get more rooms to store files to SAM. Use the command:

du -s * .[a-zA-Z]* | sort -n

get an idea of which file is the largest one so that you could deal with them.