Bash

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manual, refs


bash expansion : ranges

$ echo {d..h}
d e f g h

$ echo {d..Z}
d c b a _ ^ ]  [ Z

For more information, refer wiki.bash-hackers.org.


redirection

### cp file1 file2와 같다
$ cat < file1 > file2


string : $''

$ # Single quotation in single qoute
$ # http://stackoverflow.com/a/16605140/766330
$ echo \'sdlfkjsldf\' | sed $'s/\'//'
sdlfkjsldf'
$ #   $'string' : this is special.
$ #   below line won't work.
$ #   echo \'sdlfkjsldf\' | sed 's/\'//‘

[1]


or

$ # 'or' 
$ if [ -z "$1" ] || [ -z "$2" ]; then
>    echo "Usage: `basename $0` rslt_file target_folder"
> fi

ref. expressions used with if


extract tar archive from stdin

use - as the input file

cat largefile.tgz.aa largefile.tgz.ab | tar zxf -

[2]


find out what is using TCP port 80

# netstat -tulpn | grep :80

-p : You should be root

[3]


read from file or stdin

while read line 
do
  echo "$line"
done < "${1:-/dev/stdin}”

${1:-…} takes $1 if defined otherwise the file name of the standard input of the own process is used

[4]


multiple arguments with one flag

깔끔한 방법이 없어보임. [5]

-o a1 -o a2 -o a3

이런식으로 계속 주는 수밖에 없는듯


long options

use `getopt`(not `getopts`) [6]