It can be annoying that the ‘cp’ command keep prompting if you are to overwrite some files. This is due the cp alias. To fix that,
unalias cp cp -af source target
done.
Tag: bash
Bash: Simple command to mass replace content in directory
Imagine that we need to mass change the content in certain directory. A combination of find and sed can save the day. It is very to do it in perl as well.
find /your/dir -type f | xargs sed -i 's/old/new/g'
bash expect: script to handle command line prompts
expect is very useful to automate login process. I thought it is helpful when doing testing as well. A simple login script might work like this:
#!/usr/bin/env expect eval spawn "/path/program" expect "^Enter Auth Username:" send "user\n" expect "Enter Auth Password:" send "password\n"
To install expect, “yum install expect”
bash: testing conditions using if-grep
this expr can be really useful to determine if a term has been found or not using grep. short and sweet enough for me.
if [ ! -z $(echo $var | grep “cond”) ]; then echo “found”; else echo ” not found”; fi
bash: passing output from one program to another
sometimes you want to be able to pass output from one program to another, say from bash to php. There is a neat trick to do it. In php, we execute the bash script restartapache.
<?php
$command="/usr/local/bin/restartapache {$_GET['server']}";
exec($command, $output); foreach ($output as $v)
{ echo "$v <br/>"; }
?>
then in the bash, we write the output to a file. cat the file, then remove it.
#!/bin/bash # # $Id$ # restart apache in a server # bernard - 29 Jan 2009 # name=`basename $0` if [ $# != 1 ] then cat <&1 /tmp/$$ cat /tmp/$$ rm /tmp/$$ exit 0;
find all hidden files in a directory and delete
This turns out to be much slightly tricky. I came up with this solution
find . -type f | grep '\/\.[^.]*' | xargs rm -rf