tcsh on A Scripter's Notes

Installing custom fonts in Linux

Thu, 27 Mar 2014 13:42:19 -0400

I’ll step through how to set custom fonts for xterm terminal. My default shell is tcsh.

Create a folder .fonts in your $HOME directory.
Download fonts of your choice (ttf or otf format to ~/.fonts).
Refresh the fonts cache with fc-cache -fv.
You can verify if your custom fonts got added to the cache using fc-list. For example, I would do fc-list -f "%{family}\n" | sort -u | grep 'Inconsolata'¹ to check if my downloaded Inconsolata fonts got into the font cache.
Add the below .Xdefaults snippet to your ~/.Xdefaults
Add xrdb -merge $HOME/.Xdefaults to your shell init script. My shell init script is ~/.alias.

*customization: -color
XTerm*termName: xterm-256color

xterm*saveLines: 500
xterm*scrollBar: false
xterm*cursorColor: white
xterm*pointerColor: white
xterm*Foreground: white
xterm*Background: black
xterm*c132: true
xterm*loginShell: false

! Fonts
! XTerm*faceName: DejaVu Sans Mono:size=11
! XTerm*faceName: Inconsolata:size=11
! XTerm*faceName: Inconsolata\\-dz:style=dz:size=11
XTerm*faceName: Inconsolata\\-g:style=g:size=11

Done! Now source your shell init script and launch xterm.

Note: In order to use font names with hyphens in them, I had to escape them by using \\. So for the Inconsolata-g font, I have XTerm*faceName: Inconsolata\\-g:style=g:size=11.

It might be helpful to add the below aliases to your tcsh init script for quick font refresh and check, using fontsrefresh; fontsavail | grep 'Inconsolata'.

alias fontsavail 'fc-list -f "%{family}\n" | sort -u'
alias fontsrefresh 'fc-cache -fv'

You can download Inconsolata font from here. ↩︎

How to remove duplicate lines using awk?

Thu, 20 Mar 2014 16:11:24 -0400

If you type echo "Hi\nHow\nHi\nAre\nHi\nYou?\nAre", you will get this in your terminal:

Hi
How
Hi
Are
Hi
You?
Are

Here’s how we can remove the duplicate lines using awk ..

echo "Hi\nHow\nHi\nAre\nHi\nYou?\nAre" | awk '\!x[$0]++'

The above will give this output:

Hi
How
Are
You?

The escape char \ is required for ! in tcsh.

This is how that awk snippet works:

Initially the x array will be empty.
When $0 is Hi, x[$0]=x[Hi]=0. So !x[Hi] will be True and it will be printed out.
After that the x[Hi] becomes 1 because of the ++ increment operator.
Next time when $0==Hi, as x[Hi]==1, !x[Hi] will be False and so $0 won’t be printed out.

Using sed

Mon, 17 Mar 2014 09:31:29 -0400

sed stands for stream editor.

This is the most common way of my sed usage:

echo [SOMETHING] | sed 's/old/NEW/g'

Based on that, I have this tcsh alias¹ to get timestamps that I use to append to quick tar backups.

alias gettimestamp 'date | tr " :" "__" | sed '"'"'s/_[0-9]*_EDT.*//g'"'"''

Learn about sed from [here][s1].

Note how single quotes are escaped inside single-quoted alias definitions in tcsh. [s1]: http://www.grymoire.com/Unix/Sed.html ↩︎

Writing aliases with optional arguments in tcsh

Wed, 12 Mar 2014 11:46:49 -0400

Some times I would need to define an alias in tcsh which can have optional arguments. tcsh doesn’t seem to support that directly.

Here’s how I solve that problem.

If you have an alias alias test 'echo \!:1*' and if you run test abc def, you will get the output abc def.

!:1* prints out all the arguments starting from argument 1 till the last where even argument 1 is optional. If that argument doesn’t exist, the variable will be assigned a null value.

But tcsh will not complain about it – the * after !:1 is the beauty. On the other hand, if I have an alias alias test2 'echo \!:1', and if I run test – with zero arguments – tcsh will give an error.

So extending that, I have the below alias defined to grab an argument of any index.

alias opt_args 'set arg1 = `echo \!:1* | awk '"'"'{ print $1 }'"'"'`; \\
 echo -n "Arg num 1 = $arg1 "; \\
 set arg2 = `echo \!:2* | awk '"'"'{ print $1 }'"'"'`; \\
 echo -n "Arg num 2 = $arg2 "; \\
 set arg3 = `echo \!:3* | awk '"'"'{ print $1 }'"'"'`; \\
 echo -n "Arg num 3 = $arg3 "; \\
 echo ""; \\
 '

You can test this alias by running these commands:

opt_args abc
opt_args abc def
opt_args abc def ghi
opt_args abc def ghi jkl

Escaping dollar signs in tcsh

Thu, 06 Mar 2014 16:12:56 -0500

I found how to escape a $ sign in a regex expression in a tcsh alias. BUT it is UGLY!

I wanted to set an alias for a find command containing the -regex switch. For simplicity I will use this example:

find . -type f -regex '.*\.txt$'

This expression simply gives a list of all *.txt files in any directory under the current path.

The above command works fine when running in the terminal, but when saving that to a tcsh alias, that $ needs to be escaped:

alias findtxt "find . -type f -regex '.*txt'\"\$"''"

A simple $ has to be written as '\"\$"'!!!

Granted that I will usually get the same result if I did alias findtxt "find . -type f -regex '.*txt'" instead. But this turned out to be an interesting exercise on how to escape a $.

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