bash memo

bash-memo.sh

#!/bin/bash

## TEXT MANIPULATION ##

### CUT ###

# print the fields from second fields to last.
echo 'a\tb\tc' | cut -d$'\t' -f 2-
# b       c

# print the fields from second fields to last.
echo 'a b c d e f g h i' | cut -d ' ' -f 2-5
# b c d e

# print 2nd and 4th character
echo 'Hello' | cut -c '2,4'
# el

### TR ###

# replace all sequences of multiple spaces with just one space.
echo 'Worl   d' | tr -s ' ' ' '
# Wor d

# delete except only character
echo 'abacaba' | tr -dc 'a'
# aaaa%                                                                                        

# exclude a character
echo 'abacaba' | tr -d 'a' 
# bcb

### SORT ###

# Output the text file with the lines reordered in reverse lexicographical order
sort -r

# Sort the data in ascending order of the second column as number
sort -t $'\t' -k 2 -nsort -t $'\t' -k 2 -n

### UNIQ ###

# count the number of times each line repeats itself
uniq -c tmp.txt
# 2 00
# 2 01
# 2 00

# count the number of times each line repeats itself with CASE INSENSITIVE
uniq -c -i | sed 's/^\s*//g'

# only print unique lines
# A00
# a00
# 01
# 01
# 00
# 00
# 02
# 02
# 03
# aa
# aa
# aa
uniq -u tmp.txt
# A00
# a00
# 03

### PASTE ###

# Join all lines
# 00
# 00
# 01
paste -s tmp.txt
# 00      00      01

# rows are folded into one line with ';' separated
paste -s -d ';' tmp.txt
# 00;00;01%

# three consecutive rows are folded into one line 
paste -d ','  - - - < capital.txt

# merge two file with \t separated
paste -d '\t' state.txt capital.txt

## ARRAY ##