Useful Unix/Linux bash functions

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/’  
# or
# echo "$1" | tr -s  ‘[:lower:]’  ‘[: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 \;

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