funcshional

Functional style shell commands

Command	Description
foldl	Accumulate results over lines
foldl1	Like foldl, but initialize with first line
ix	Pick nth whitespace-delimited text out of each line
map	Run a command on each line
mapDir	Run a command in each directory

foldl

foldl <cmd> <init>

Runs cmd with variables $x and $y available for expansion, with accumulation in x, starting with init.

nstepp $ ls -l
total 56
-rw-r--r--  1 nstepp  nstepp  1068 Dec  7 12:08 LICENSE
-rw-r--r--  1 nstepp  nstepp    46 Dec  7 12:08 README.md
-rwxr-xr-x  1 nstepp  nstepp   182 Dec  7 11:12 foldl
-rwxr-xr-x  1 nstepp  nstepp   128 Dec  7 11:12 foldl1
-rwxr-xr-x  1 nstepp  nstepp   108 Dec  7 11:13 ix
-rwxr-xr-x  1 nstepp  nstepp   138 Dec  7 11:13 map
-rwxr-xr-x  1 nstepp  nstepp   205 Dec  7 11:13 mapDir
nstepp $ ls -l | ix 5 | foldl 'echo $((x+y))' 0
1875
nstepp $

foldl1

foldl1 <cmd>

Runs cmd with variables $x and $y available for expansion, with accumulation in x, starting with the first available line.

nstepp $ ls -l
total 56
-rw-r--r--  1 nstepp  nstepp  1068 Dec  7 12:08 LICENSE
-rw-r--r--  1 nstepp  nstepp    46 Dec  7 12:08 README.md
-rwxr-xr-x  1 nstepp  nstepp   182 Dec  7 11:12 foldl
-rwxr-xr-x  1 nstepp  nstepp   128 Dec  7 11:12 foldl1
-rwxr-xr-x  1 nstepp  nstepp   108 Dec  7 11:13 ix
-rwxr-xr-x  1 nstepp  nstepp   138 Dec  7 11:13 map
-rwxr-xr-x  1 nstepp  nstepp   205 Dec  7 11:13 mapDir
nstepp $ ls -l | ix 5 | foldl1 'echo $((x+y))'
1875
nstepp $

ix

ix <num>

Picks the numth word. Equivalent to awk '{ print $num; }'.

nstepp $ ls -l
total 56
-rw-r--r--  1 nstepp  nstepp  1068 Dec  7 12:08 LICENSE
-rw-r--r--  1 nstepp  nstepp    46 Dec  7 12:08 README.md
-rwxr-xr-x  1 nstepp  nstepp   182 Dec  7 11:12 foldl
-rwxr-xr-x  1 nstepp  nstepp   128 Dec  7 11:12 foldl1
-rwxr-xr-x  1 nstepp  nstepp   108 Dec  7 11:13 ix
-rwxr-xr-x  1 nstepp  nstepp   138 Dec  7 11:13 map
-rwxr-xr-x  1 nstepp  nstepp   205 Dec  7 11:13 mapDir
nstepp $ ls -l | ix 5
1068
46
182
128
108
138
205
nstepp $

map

map <cmd>

Runs a command on each line (like a simplified xargs)

nstepp $ find .. -name '*.md'
../funcshional/README.md
nstepp $ find .. -name '*.md' | map basename
README.md
nstepp $

mapDir

mapDir <cmd>

Runs a command in each directory specified by input lines.

nstepp $ find .. -name '*.md'
../funcshional/README.md
nstepp $ find .. -name '.git' | map dirname | mapDir "git status" 
On branch master
Your branch is up-to-date with 'origin/master'.
nothing to commit, working tree clean
nstepp $