Linux Tips

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Revision as of 16:12, 14 October 2011 by Roux (talk | contribs) (The coma to point)

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The coma to point conversion in French environment

if you are working with a configuration of linux which has not the dot "." as a standard format for floating points data (for instance the coma "," in french), you can add the following two lines in your .bashrc file:

LC_NUMERIC=en_US
export LC_NUMERIC

this will make the job without too many side effects.

Handling jobs

  • if you want to send a job on a computer and logout without killing the job:
:> nohup ./job

Transferring files

  • the scp command:
:> scp server:directory here
  • if you do some regular updates, there is no -update option to scp. Then, better use the rsync command. For instance with
:> rsync -avub -e ssh server:data/*.gz data/

be careful with the slash after directory names, with or without is no exactly the same behavior. Look at man rsync before using it.

working with zip files

Linux usually provides a couple of command piping gzip

zgreg, zcat, zdiff, zless, zmore, zegrep,...

Here is a simple extension of tail and head for zipped files, that you can call ztail and zhead (example is for tail, replace "tail" with "head" everywhere to get zhead) and add to your own /bin directory:

#!/bin/bash
PATH=${GZIP_BINDIR-'/bin'}:$PATH

usage="Usage: $0 [OPTIONS]... [FILES]...
Like 'tail', but operate on the uncompressed contents of any compressed FILEs.

Options are the same as for 'tail'."

case $1 in
--help)    exec echo "$usage";;
-h)        exec echo "$usage";;
esac

options=""
files=""
for i in $@; do
str="$i"
if test -f $i && [ ${str:(-3)} = ".gz" ]; then
    files=$files"$i "
else
    if [ ${str:0:1} = "-" ] && [ $str != "-v" ] && [ $str != "--verbose" ]; then
        options=$options"$i "
    elif [ $str != "-v" ] && [ $str != "--verbose" ]; then
        echo -ne "***Warning: $i is neither a regular zip file or a regular option***\n\n"
    fi
fi
done

for file in $files; do
    echo "==>"$file"<=="
    exec gzip -cd $file | tail $options
done