unix

Unix (all-caps UNIX for the trademark) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, developed in the 1970s at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others. read more at WikiPedia

  • tatice-linux-tux-10409

    Some useful Bash Linux alias taken from my user profile. If you have a long command that you type frequently consider putting it in as an alias.

    In computing, alias is a command in various command line interpreters (shells) such as Unix shells, 4DOS/4NT and Windows PowerShell, which enables a replacement of a word with another string. It is mainly used for abbreviating a system command, or for adding default arguments to a regularly used command. [WikiPedia]

    Description &160;
    Find all directories and and chmod them to rwxr.xr.x alias fixpermD='find . -type d -exec chmod 755 {} \;'
    Find all files and and chmod them to rw.r..r.. alias fixpermF='find . -type f -exec chmod 644 {} \;'
    Both above and set recursively user and user group in one shot alias fixUserAPerms='fixpermF; fixpermD; chown -R userA .;chgrp -R usergrp .'
    Make a directory and all files recursively read only, secure but a pain to maintain. see next&160; alias ro='find . -type f -exec chmod 444 {} \;find . -type d -exec chmod 555 {} \;'
    Make a directory and all files recursively read write, just the time to update your site. alias rw='find . -type f -exec chmod 644 {} \;find . -type d -exec chmod 755 {} \;'
    Lower case all files in current directory alias lowercaseallfiles='for f in *; do mv $f `echo $f | tr [:upper:] [:lower:]`; done'
    List all open connections to your server alias listOpenConnections='lsof –i'
    List all internet connections alias listinternetconnection='netstat –lptu'
    find the 10 biggest in size directories alias dirsizes=’du -cks * | sort -n | tail –10'
    Show open port alias openports='netstat -nape --inet'
  • The Alternative PHP Cache (APC) is a free and open opcode cache for PHP. It was conceived of to provide a free, open, and robust framework for caching and optimizing PHP intermediate code. from http://nl2.php.net/apc

    Links:
    Unpack your distribution file. You will have downloaded a file named something like apc_x.y.tar.gz. Unzip this file with a command like
    # wget http://pecl.php.net/get/APC-3.0.14.tgz
    # gunzip apc_x.y.tar.gz

    Next you have to untar it with
    #  tar xvf apc_x.y.tar

    This will create an apc_x.y directory. cd into this new directory:
    # cd apc_x.y

    phpize is a script that should have been installed with PHP, and is normally located in /usr/local/php/binassuming you installed PHP in /usr/local/php. (If you do not have the phpize script, you must reinstall PHP and be sure not to disable PEAR.).

    Locate phpize:
    # find / -name phpize

    mine is in
     /etc/alternatives/phpize
    yours may be in /usr/local/php/bin/phpize

    Run the phpize command:
    #  /usr/local/php/bin/phpize

    Its output should resemble this:
            Configuring for:
              PHP Api Version:   20020918
              Zend Module Api No:   20020429
              Zend Extension Api No:   20021010


    phpize should create a configure script in the current directory. If you get errors instead, you might be missing some required development tools, such as autoconf or libtool. You can try downloading the latest versions of those tools and running phpize again.

    Run the configure script.

    phpize creates a configure script. The only option you need to specify is the location of your php-config script.

    find location of php-config
    # find / -name php-config
    then
    # ./configure --enable-apc --enable-apc-mmap --with-apxs --with-php-config=/etc/alternatives/php-config

    php-config should be located in the same directory as phpize.
    If you prefer to use mmap instead of the default IPC shared memory support,  add --enable-apc-mmap to your configure line.

        If you prefer to use sysv IPC semaphores over the safer fcntl() locks, add --enable-sem to your configure line.  If you don't have a problem
        with your server segaulting, or any other unnatural accumulation of semaphores on your system, the semaphore based locking is slightly faster.

    Compile and install the files.
    Simply type:
    # make install
    Installing shared extensions:     /usr/lib/php5/extensions/


    Suggested Configuration (in your php.ini file)

      extension=apc.so
      apc.enabled=1
      apc.shm_segments=1
      apc.shm_size=128
      apc.ttl=7200
      apc.user_ttl=7200
      apc.num_files_hint=1024
      apc.mmap_file_mask=/tmp/apc.XXXXXX
      apc.enable_cli=1



    Although the default APC settings are fine for many installations, serious
    users should consider tuning the following parameters:

        OPTION                  DESCRIPTION
        ------------------      --------------------------------------------------
        apc.enabled             This can be set to 0 to disable APC. This is
                                primarily useful when APC is statically compiled
                                into PHP, since there is no other way to disable
                                it (when compiled as a DSO, the zend_extension
                                line can just be commented-out).
                                (Default: 1)

        apc.shm_segments        The number of shared memory segments to allocate
                                for the compiler cache. If APC is running out of
                                shared memory but you have already set
                                apc.shm_size as high as your system allows, you
                                can try raising this value.  Setting this to a
                                value other than 1 has no effect in mmap mode
                                since mmap'ed shm segments don't have size limits.
                                (Default: 1)

        apc.shm_size            The size of each shared memory segment in MB.
                                By default, some systems (including most BSD
                                variants) have very low limits on the size of a
                                shared memory segment.
                                (Default: 30)

        apc.optimization        This option has been deprecated.
                                (Default: 0)

        apc.num_files_hint      A "hint" about the number of distinct source files
                                that will be included or requested on your web
                                server. Set to zero or omit if you're not sure;
                                this setting is mainly useful for sites that have
                                many thousands of source files.
                                (Default: 1000)

        apc.user_entries_hint   Just like num_files_hint, a "hint" about the number
                                of distinct user cache variables to store.
                                Set to zero or omit if you're not sure;
                                (Default: 4096)

        apc.ttl                 The number of seconds a cache entry is allowed to
                                idle in a slot in case this cache entry slot is
                                needed by another entry.  Leaving this at zero
                                means that your cache could potentially fill up
                                with stale entries while newer entries won't be
                                cached.
                                (Default: 0)

        apc.user_ttl            The number of seconds a user cache entry is allowed
                                to idle in a slot in case this cache entry slot is
                                needed by another entry.  Leaving this at zero
                                means that your cache could potentially fill up
                                with stale entries while newer entries won't be
                                cached.
                                (Default: 0)


        apc.gc_ttl              The number of seconds that a cache entry may
                                remain on the garbage-collection list. This value
                                provides a failsafe in the event that a server
                                process dies while executing a cached source file;
                                if that source file is modified, the memory
                                allocated for the old version will not be
                                reclaimed until this TTL reached. Set to zero to
                                disable this feature.
                                (Default: 3600)

     apc.cache_by_default    On by default, but can be set to off and used in
                                conjunction with positive apc.filters so that files
                                are only cached if matched by a positive filter.
                                (Default: On)

        apc.filters             A comma-separated list of POSIX extended regular
                                expressions. If any pattern matches the source
                                filename, the file will not be cached. Note that
                                the filename used for matching is the one passed
                                to include/require, not the absolute path.  If the
                                first character of the expression is a + then the
                                expression will be additive in the sense that any
                                files matched by the expression will be cached, and
                                if the first character is a - then anything matched
                                will not be cached.  The - case is the default, so
                                it can be left off.
                                (Default: "")

        apc.mmap_file_mask      If compiled with MMAP support by using --enable-mmap
                                this is the mktemp-style file_mask to pass to the
                                mmap module for determing whether your mmap'ed memory
                                region is going to be file-backed or shared memory
                                backed.  For straight file-backed mmap, set it to
                                something like /tmp/apc.XXXXXX (exactly 6 X's).
                                To use POSIX-style shm_open/mmap put a ".shm"
                                somewhere in your mask.  eg.  "/apc.shm.XXXXXX"
                                You can also set it to "/dev/zero" to use your
                                kernel's /dev/zero interface to anonymous mmap'ed
                                memory.  Leaving it undefined will force an
                                anonymous mmap.
                                (Default: "")

        apc.slam_defense        ** DEPRECATED - Use apc.write_lock instead **
                                On very busy servers whenever you start the server or
                                modify files you can create a race of many processes
                                all trying to cache the same file at the same time.
                                This option sets the percentage of processes that will
                                skip trying to cache an uncached file.  Or think of it
                                as the probability of a single process to skip caching.
                                For example, setting this to 75 would mean that there is
                                a 75% chance that the process will not cache an uncached
                                file.  So the higher the setting the greater the defense
                                against cache slams.  Setting this to 0 disables this
                                feature.
                                (Default: 0)

        apc.file_update_protection
                                When you modify a file on a live web server you really
                                should do so in an atomic manner.  That is, write to a
                                temporary file and rename (mv) the file into its permanent
                                position when it is ready.  Many text editors, cp, tar and
                                other such programs don't do this.  This means that there
                                is a chance that a file is accessed (and cached) while it
                                is still being written to.  This file_update_protection
                                setting puts a delay on caching brand new files.  The
                                default is 2 seconds which means that if the modification
                                timestamp (mtime) on a file shows that it is less than 2
                                seconds old when it is accessed, it will not be cached.
                                The unfortunate person who accessed this half-written file
                                will still see weirdness, but at least it won't persist.
                                If you are certain you always atomically update your files
                                by using something like rsync which does this correctly, you
                                can turn this protection off by setting it to 0.  If you
                                have a system that is flooded with io causing some update
                                procedure to take longer than 2 seconds, you may want to
                                increase this a bit.
                                (Default: 2)

        apc.enable_cli          Mostly for testing and debugging.  Setting this enables APC
                                for the CLI version of PHP.  Normally you wouldn't want to
                                create, populate and tear down the APC cache on every CLI
                                request, but for various test scenarios it is handy to be
                                able to enable APC for the CLI version of APC easily.
                                (Default: 0)

        apc.max_file_size       Prevents large files from being cached.
                                (Default: 1M)

        apc.stat                Whether to stat the main script file and the fullpath
                                includes.  If you turn this off you will need to restart
                                                                                            

     apc.write_lock          On busy servers when you first start up the server, or when
                                many files are modified, you can end up with all your processes
                                trying to compile and cache the same files.  With write_lock
                                enabled, only one process at a time will try to compile an
                                uncached script while the other processes will run uncached
                                instead of sitting around waiting on a lock.
                                (Default: 1)

        apc.report_autofilter   Logs any scripts that were automatically excluded from being
                                cached due to early/late binding issues.
                                (Default: 0)

        apc.rfc1867             RFC1867 File Upload Progress hook handler is only available
                                if you compiled APC against PHP 5.2.0 or later.  When enabled
                                any file uploads which includes a field called
                                APC_UPLOAD_PROGRESS before the file field in an upload form
                                will cause APC to automatically create an upload_<key>
                                user cache entry where <key> is the value of the
                                APC_UPLOAD_PROGRESS form entry.

                                Note that the file upload tracking is not threadsafe at this
                                point, so new uploads that happen while a previous one is
                                still going will disable the tracking for the previous.
                                (Default: 0)

        apc.localcache          This enables a lock-free local process shadow-cache which
                                reduces lock contention when the cache is being written to.
                                (Default: 0)

        apc.localcache.size     The size of the local process shadow-cache, should be set to
                                a sufficently large value, approximately half of num_files_hint.
                                (Default: 512)

        apc.include_once_override
                                Optimize include_once and require_once calls and avoid the
                                expensive system calls used.
                                (Default: 0)

     
  • Official version of nginx for Ubuntu Precise is 1.1.19 but the latest available stable version is 1.2.2 (Changes), In this post I will present you how to update to the latest available version.

    vi /etc/apt/sources.list

    and add depending on your Ubuntu version either

    For Ubuntu 10.04 Lucid:

    deb http://nginx.org/packages/ubuntu/ lucid nginx
    deb-src http://nginx.org/packages/ubuntu/ lucid nginx

    For Ubuntu 12.04 Precise:

    deb http://nginx.org/packages/ubuntu/ precise nginx
    deb-src http://nginx.org/packages/ubuntu/ precise nginx

    Now you can run

    apt-get update

    When using the public nginx repository for Ubuntu, you’ll get this error

    W: GPG error: http://nginx.org lucid Release: The following signatures 
    couldn't be verified because the public key is not available: NO_PUBKEY ABF5BD827BD9BF62

    First of all this is only warning and you can ignore it, if you know what are you doing and in case you prefer to add public key, used for signing packages and repository, just run:

    gpg -a --export 7BD9BF62 |  sudo apt-key add -

    or

    wget http://nginx.org/packages/keys/nginx_signing.key
    cat nginx_signing.key | sudo apt-key add -

    apt-get update should now run fine, however after running an

    apt-get install nginx

    you may still get this kind of error:

    dpkg: error processing /var/cache/apt/archives/nginx_1.2.2-1~precise_amd64.deb (--unpack):
     trying to overwrite '/etc/logrotate.d/nginx', which is also in package nginx-common 1.1.19-1
    dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)
    Errors were encountered while processing:
     /var/cache/apt/archives/nginx_1.2.2-1~precise_amd64.deb

    just remove nginx-common and retry

    apt-get remove nginx-common

    More at http://wiki.nginx.org/Install

  • tatice-linux-tux-10409

    For day to day hacker, they may be more elegant ways to do it (PERL, AWK), but they have work well for me.

    • Upper case file name or variable,
    • Search and replace in all files content recursively,
    • Renaming all files recursively,
    • Renaming all directory recursively,
    • Copying a set of files from one directory to the other and preserving hierarchy.

    Upper case file name or variable

    function toUpper {
    echo "$1" | sed 'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/'&160;&160;
    # or
    # echo "$1" | tr -s&160; '[:lower:]'&160; '[:upper:]'
    }

    Usage:

    • in a script toUpper “cedric”
    • assign to a variable in a script result=$(toUpper $variable) or result=$(toUpper “cedric”)

    Search and replace in all files content recursively

    This can go through all directories

    • $3 as base directory
    • Search for $1
    • Replace with $2

    function searchAndReplaceRecursively {
    echo "replace '$1' with '$2' in dir '$3'";
    for file in `find $3 -type f`;
    do
    echo -ne ".";
    sed -e 's/'$1'/'$2'/g' $file > /tmp/tempfile.tmp
    mv /tmp/tempfile.tmp $file
    done
    echo "";
    }

    Usage:

    • in a script searchAndReplaceRecursively “cedric” “unix” .

    Renaming all files recursively

    This can go through all directories, renaming all files based on parameters:

    • $3 as base directory,
    • Search for $1 in filename,
    • Replace with $2 in filename.

    function renameFilenameRecursively {
    for file in `find $3 -type f`;
    do
    newFilename=`basename $file | sed -e 's/'$1'/'$2'/g'`;
    dirs=`dirname $file`;
    mv $file $dirs/$newFilename;
    done
    }

    Usage:

    • in a script renameFilenameRecursively “cedric” “unix” .

    Renaming all directory recursively

    This can go through all directories, renaming all directories based on parameters:

    • $3 as base directory
    • Search for $1 in directory name
    • Replace with $2 in directory name
    • in bold, you can put either
      • *$1 the pattern has to be at end of directory name,
      • $1* the pattern has to be at beginning of directory name,
      • *$1* the pattern has to be in the middle of directory name,
      • remove the case all together, the grep $1 filter already the result of the command find.

    function renameDirectoriesRecursively {
    for adir in `find $3 -type d | grep $1`;
    do
    case $adir in
    *$1* )
    newdirname=$( echo "$adir" | sed -e 's/'$1'/'$2'/g' );
    echo Found $adir will be renamed to $newdirname;
    mv $adir $newDirName;
    esac
    done
    }

    Usage:

    • in a script renameDirectoriesRecursively “cedric” “unix” .

    Copying a set of files from one directory to the other and preserving hierarchy

    # find . -name $1 -exec cp -r --parents {} $destination \;