Bash Notes | directedge.us

Bash Notes

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linux

Advanced command history substitution

Execute previous command with a string replacement (only works on first string)

$ ls *.tmp
$ ^ls^rm
rm *.tmp
$ cp -i file1 file2 file3 destdir

$ ^-i # no 2nd string replaces with nothing cp file1 file2 file3 destdir

Replace all occurrences of string in previous command:

$ echo 4 4 4 4 4

$ !:gs/4/5/ echo 5 5 5 5 5

Access previous commands:

$ls -l *.txt
$ !!    # run the last command
ls -l *.txt

$ !-1 # same as !! $ !-2 # run the command before the last one $ !-3 # run the 3rd previous command

Access the parameters of the previous command:

$ cp file1 file2 file3 destdir
$ echo !$
destdir

$ echo !* file1 file2 file3 destdir

Scripting

Parse command-line options:

for i in $*
do
    case $i in
    -v|--verbose)
        VERBOSE=1
        ;;
    -h=*|--host=*)
        HOST=`echo $i | sed 's/[-a-zA-Z0-9]*=//'`
        ;;
    *)
        echo "Invalid option" >&2
        ;;
    esac
done

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