Geek Lair

Archive for October 2009

Bash script to compile and run a C program in one step

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Here is a simple script to compile and run a C program:

#!/bin/bash
# Script to compile and execute a c program in one step.

# Get file name without the .c extension
file_name=$(echo $1|sed 's/\(.*\)\.c/\1/')

# Compile the program with -o option to specify the name of the binary
gcc -o $file_name.out $1

# If there were no compilation errors, run the program
if [[ $? -eq 0 ]]; then
        ./$file_name.out
fi

The same could be done for C++ programs as well. Just replace the .c in the sed expression with .cpp and replace gcc with g++

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Written by anonir

October 26, 2009 at 18:21

Posted in bash, Linux

Customizing vim

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You can set additional options in vim to make your programming life easier. You can add these options to .vimrc in your home folder so that they are loaded every time you start vim.

vim ~/.vimrc

set autoindent
set smartindent
set tabstop=4
set shiftwidth=4
syntax on
colo murphy

To know what each option does,  just type:

:help <option>

For example to know about autoindent, type:

:help autoindent

gvim

By default, gvim uses courier font. To set your own font, create a file .gvimrc in your home and add set guifont option:

vim ~/.gvimrc

set guifont=Bitstream\ Vera\ Sans\ Mono\ 9

Another useful option is to set the window size:

set lines=100 columns=130

Note that gvim reads options from .vimrc as well. But vim will not read options from .gvimrc

Other resources of interest

Written by anonir

October 26, 2009 at 18:04

Posted in Linux

Tagged with ,

bash and cron

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Setting up cron in Ubuntu is simple enough as described in the Ubuntu wiki. But what they don’t mention is that by default cron uses /bin/sh for its SHELL env variable. That may cause a problem if you try to set up a bash script in cron. To prevent that from happening, you need to define the SHELL variable for your user crontab to point to /bin/bash.

In the console type:

crontab -e

Add the following line at the top:

SHELL=/bin/bash

Your crontab should look something like this:

SHELL=/bin/bash
# m h  dom mon dow   command
*/5 * * * * /usr/local/bin/my_bash_script

Written by anonir

October 13, 2009 at 15:45

Posted in bash, Linux, Ubuntu

Tagged with ,