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shell-utils

Utilities and helper methods for shell programming (bash)

This project contains:

collections.shm

a module providing basic collections functionality (List, Set and Map) for small collections.

Sometimes when creating shell scripts, it would be nice to have basic collections such as a List, Set or a Map. Therefore I created a shell module providing a List, Set and Map implementation based on flat files and tools like grep, tail, head, etc. The files storing the collection data are automatically deleted when exiting the script.

  • List Example usage:

    #load the module
. shell-utils/lib/collections.shm

# add some entries to the list
collections_list_push mylist "entry 1"
collections_list_push mylist "entry 2"
collections_list_push mylist "entry 3"

# iterate over each list element
for e in "$(collections_list_all mylist)"; do
    echo "$e"
done

collections_list_shift mylist # echoes "entry 1"
echo $(collections_list_size mylist) # echoes 2
collections_list_get mylist 0 # echoes "entry 2"

  • List functions (parameters):

    • collections_list_all (identifier)

      echoes all the values of the list identified by identifier

    • collections_list_delete (identifier, index)

      deletes the value at index of the list identified by identifier

    • collections_list_get (identifier, index)

      echoes the value at index of the list identified by identifier

    • collections_list_insert (identifier, index, value)

      inserts the given value at index of the list identified by identifier

    • collections_list_push (identifier, value)

      add the given value at the end of the list identified by identifier

    • collections_list_unshift (identifier, value)

      add the given value at the beginning of the list identified by identifier

    • collections_list_pop (identifier)

      echoes and removes the value at the end of the list identified by identifier

    • collections_list_shift (identifier)

      echoes and removes the value at the beginning of the list identified by identifier

    • collections_list_size (identifier)

      echoes the number of elements inside the list identified by identifier

    • collections_list_clear (identifier):

      clears the list identified by identifier

  • Map Example usage:

    #load the module
. shell-utils/lib/collections.shm

# populate the map with some data
for i in $(seq 1 10); do
  collections_map_put mymap "key${i}" "value ${i}"
done

# iterate over the keys
for key in $(collections_map_keys mymap); do
  # get the value for key
  echo "key: ${key}, value: "$(collections_map_get mymap $key)
done

  • Map functions (parameters):

    • collections_map_contains (identifier, key):

      checks whether the key exists in the map identified by identifier, returns true if the key exists

    • collections_map_delete (identifier, key):

      deletes the key and it's value from the map identified by identifier

    • collections_map_get (identifier, key):

      echoes the value for key from the map identified by identifier

    • collections_map_keys (identifier):

      echoes all the keys from the map identified by identifier

    • collections_map_put (identifier, key, value):

      stores the given key / value pair in the map identified by identifier

    • collections_map_size (identifier):

      echoes the number of key / value pairs of the map identified by identifier

    • collections_map_clear (identifier):

      clears the map identified by identifier

  • Set Example usage:

    #load the module
. shell-utils/lib/collections.shm

# populate the set with some data
for i in $(seq 1 10); do
    collections_set_put myset "item $i"
done

# check if specific items exist:
collections_set_contains myset "item 1" && echo "item 1 exists" # echoes "item 1 exists"
collections_set_contains myset "item 11" && echo "item 11 exists" # echoes nothing

# delete item
collections_set_delete myset "item 1"
collections_set_contains myset "item 1" && echo "item 1 exists" # echoes nothing

  • Set functions (parameters):

    • collections_set_contains (identifier, item)

      checks whether the item is inside the set identified by identifier, returns true if the item exists

    • collections_set_delete (identifier, item)

      removes the item from the set identified by identifier

    • collections_set_items (identifier)

      echoes all the items of the set identified by identifier

    • collections_set_put (identifier, item)

      puts the item into the set identified by identifier

    • collections_set_size (identifier)

      echoes the number of items inside the set identified by identifier

    • collections_set_clear (identifier):

      clears the set identified by identifier