Web Development & Stuff » Linux

Linux batch file rename

admin — Tue, 24 May 2011 13:59:30 +0000

For my own records. Batch file rename using shell:

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Rename all jpg files that contain the string 19_ and replace it with 28_

for file in *.jpg ; do mv $file `echo $file | sed 's/19_/28_/g'` ; done

File uploads to PHP scripts hang in Safari bug

admin — Tue, 15 Jun 2010 17:37:31 +0000

I was experiencing this issue with some larger file uploads using the CakePHP Media plugin.

https://bugs.webkit.org/show_bug.cgi?id=5760

I added this to the virtual host declaration in my Apache config file to fix it:

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<VirtualHost x.x.x.x:x>

    # Prevent Safari from hanging on uploads

    BrowserMatch  Safari  nokeepalive

VirtualHost>

Set setgid bit (group id) on directory giving group ownership/permissions

admin — Tue, 19 Jan 2010 16:02:05 +0000

For my own records, had to look this up again today so thought best blog it:

1 2	sudo chmod -R g+s * # Would set group permissions recursively for all directories at the current location.

If anyone is interested, files in these directories will have the group ownership as the directory, instead of the group of the user that created the file. Which is very handy if you have a user group all working in the same set of directories/directory.

Loop over svn stat output deleting files

admin — Thu, 14 Jan 2010 14:43:17 +0000

I had the issue where my MacBook creates files prefixed with ._ while working on a Samba share. I’ve fixed this once before but it was so long ago, I’ve forgotten how!! Anyway, I had a stack of these files in a checked-out svn project and needed to delete them. Rather than do each one individually I put together this Bash command that loops over each line outputted by svn stat, cleans it up and then removes the file.

1	svn stat \| grep -F ._ \| sed 's/? //' \| while read line; do rm -f $line; done

The grep -F looks for a literal period (.) in each line. In this case it’s a period underscore (._) string but we still need the -F.
The sed ’s/? //’ looks for the “? ” prefix and strips it.
The while loop does the rm -f on each line.

Here’s another method using xargs instead of a while loop. Also, cut is trimming 9 chars (the file status flag and the whitespace) from the front of outputted line.

1	svn stat \| grep -F ._ \| cut -c9- \| xargs rm -f

Compile and install PHP on live production server

admin — Wed, 07 Oct 2009 14:28:49 +0000

I managed to recompile PHP with some new directives and install it on my live production server with minimal downtime.

I followed these steps:

1) Downloaded the source of PHP. I stuck to the same branch (5.2) as there was nothing I required in 5.3.

2) Backed up my /etc/php.ini file.

3) Compiled PHP with ./configure using my old directives plus a few new ones. You can see what directives were used in your last compile by viewing the output of phpinfo()

4) Did the ./make and ./make test

5) Stopped Apache with apachectl stop

6) Did the ./make install

7) Started Apache with apachectl start

Worked perfectly, with about 30 seconds of downtime ;]

On reflection, next time I’ll use graceful-stop in step 5. As this will allow each Apache process to finish what it’s doing before stopping.

Return exit code of previous shell command

admin — Sat, 03 Oct 2009 14:45:37 +0000

You can return the exit/return code of the command you just ran in OSX/Linux using this simple command:

echo $?

This is handy when debugging scripts that rely on shell command return values.

Bash – Match exact string in directory listing

admin — Mon, 27 Apr 2009 16:38:44 +0000

Been doing some bash scripting of late, been meaning to for ages. Really enjoying it too!

Anyway, today I needed to match an exact string in a directory listing (ls). To check if a volume on my Mac Book was mounted, so I could backup to it. Or any other drive for that matter. I ended up using this code:

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#!/bin/bash

if [ "$1" ]; then

  # Look for an exact match of the first passed argument in /Volumes. 

  # The -x switch matches the string ($1) exactly. The -c switch counts the outputted lines.

  if [ $(ls /Volumes/ | grep -c -x "$1") == 1 ]; then

    # Do stuff...

  else

    echo 'Sorry, but no volume with that name not found.'

  fi

else

  echo 'Please pass a destination volume to this backup script as the first command line argument.'

fi

# Usage

bash$ backup.sh "Volume name"

Reload bash_profile / profile without starting a new shell session

admin — Wed, 04 Mar 2009 14:47:34 +0000

I always used to log-out / log-back-in to shell, to allow changes in my .bash_profile to kick in. I’m guessing this would work in OSX with your .profile file too but I’ve not tested it. Anyways, I discovered you can reload the script on the fly using:

1	source ~/.bash_profile

Mount remote file system on your local file system over SSH – SSHFS

admin — Wed, 25 Feb 2009 23:07:26 +0000

Lots of love going about today! This time, the recipient is SSHFS which allows you to mount a remote filing system onto your local tree over SSH. In a virtual hosting environment (/vhosts/ etc) it’s pure joy to work with.

You’ll need to install SSHFS on the client (the machine you want to mount the remote system on). All you need on the remote system is SSH. This is already installed on most systems.

You can install SSHFS on OSX with Mac Ports:

1	port install sshfs

On the local client system add the user you’re going to connect with to the fuse group. That group was created when you installed SSHFS:

1	gpasswd -a localuser fuse

Create a directory on the local filing system to use as a mount point:

1	mkdir /vhosts_servername/

Now connect to the remote system using a command line like this on the client:

1	sshfs localuser@yourdomain.com:/remote_directory/ /vhosts_servername

Nice ;]

MySQL export SQL query as file

admin — Sun, 18 Jan 2009 10:35:00 +0000

This will dump an SQL statement into a file:

1	mysql -u username -p database_name -e "SQL_STATEMENT" > file.data