cmdchallenge.com solutions

gistfile1.txt

hello_world/
    echo "hello world"
current_working_directory/
    pwd
list_files/
    ls
print_file_contents/
    cat access.log
last_lines/
    tail -n5 access.log
find_string_in_a_file/
    grep 'GET' access.log
find_tabs_in_a_file/
    grep -P '\t' file-with-tabs.txt | wc -l 
search_for_files_containing_string/
    grep -rli '500' *
search_for_files_by_extension/
    find -type f -name 'access.log*'
search_for_string_in_files_recursive/
    find -type f -name 'access.log*' | xargs -I{} cat {}|grep '500'
extract_ip_addresses/
    find -type f -name 'access.log*' | xargs awk '{print $1}'
delete_files/
    find . -delete
count_files/
    find -type f | wc -l
simple_sort/
    sort access.log
count_string_in_line/
    grep 'GET' access.log|wc -l
split_on_a_char/
    cat split-me.txt | tr ';' '\n'
print_number_sequence/
    seq 1 100 | tr '\n' ' '
remove_files_with_a_dash/
    find -type f -name '-*' -delete
remove_files_with_extension/
    find -type f -name '*.doc' -delete
remove_files_without_extension/
    find -type f \! -name '*.txt' -a \! -name '*.exe' -delete
replace_text_in_files/
    find -type f -name '*.txt' | xargs -I{} sed -i 's/challenges are difficult//g' "{}"
sum_all_numbers/
    z=0; for i in $(cat sum-me.txt); do z=$(($z + $i)); done; echo $z
just_the_files/
    find -type f | xargs -I{} basename "{}"
remove_extensions_from_files/
    for f in $(find -type f); do bn=${f%.*}; test -z "${bn}" || mv ${f} ${bn}; done
replace_spaces_in_filenames/
    find -type f | while read i; do echo "${i}" | sed 's&^./&&;s& &.&g'; done
files_starting_with_a_number/
    find -type f -name '[0-9]*' | xargs -I{} basename "{}"
print_nth_line/
    sed '25q;d' faces.txt
remove_duplicate_lines/
    #needed help on this
    awk '!x[$0]++' faces.txt
corrupted_text/
    sed 's/!\+/!/g;s/!\([a-zA-Z]\)/\1/;s/\([a-z]\)!\([a-z]\)/\1\2/;s/! \([a-z]\)/ \1/;s/!\.!/./' war_and_peace.txt
print_common_lines/
    comm -1 -2 <(sort access.log.1 | awk '{print $1}') <(sort access.log.2 | awk '{print $1}')