Text Processing Unix Commands: sort and wc
Text processing Unix commands are those affecting text and text files. For example, commands like cut, paste, cmp, sort, comm, head, tail, wc, diff, grep are few in the list. While editing files, you may lose track of what changes you have made to which files.
In this article, we will cover text processing Unix commands: sort and wc
sort command in Unix
- Ordered arrangement.
- sorts lines of text alphabetically or numerically, default sorting is alphabetical
Rules for sorting are:
1. Lines starting with a number will appear before lines starting with a letter. 2. Lines starting with letters are sorted alphabetically, lowercase case appears before tan uppercase.
Sorting rules can be changed using OPTIONS.
SYNTAX: sort [OPTION]..[FILE]..
Option -d dictionary order sort Option -n arithmetic/numeric order Option -r reverse order Option –k n Sorts on field n Option –b ignore leading blanks Option –m Merge (not sort)
Example:
$cat file1.txt apples trees plants sun bananas
sort the lines in this file alphabetically
use the following command:
$sort file1.txt apples bananas pears sun trees
Note that this command does not actually change the input file, file1.txt. If you want to write the output to a new file, file2.txt, redirect the output like this:
$sort file1.txt > file2.txt $cat file2.txt apples bananas pears sun trees
Sorting In Reverse Order
You can perform a reverse-order sort using the -r flag.$ sort -r file1.txt Output: trees sun pears bananas apples
wc command in Unix
-
-
- Counts and displays the number of lines, words and characters in a file.
- By default it displays four-columnar output.
- 4 columns are :the number of lines, words, byte counts and the name of the file passed as argument.
-
SYNTAX: wc [OPTION].. [FILE]..
| Options |
Use |
| -l |
Displays the number of lines in a file. |
|
-w |
Displays the number of words in a file. |
|
-c |
Displays the count of bytes in a file. |
|
-m |
Prints the count of characters from a file. |
|
-L |
Prints only the length of the longest line in a file. |
Example:
$ wc /myData/file1 Output: 112 3345 23234 /myData/file1
112 is the number of lines. 3345 is the number of words. 2323 is the number of characters.
$ wc -w /myData/file1 Output: 3345 /myData/file1
-w option displays the word count.
$ wc -l /myData/file1 Output: 112 /myData/file1
-l option displays the line count.
Display information of more than one File using wc command
You can see information of more than one file by passing filename to the argument.
SYNTAX: wc [OPTION].. [FILE1][FILE2]
Example:
$ wc /myData/file1 /myData/file2 Output: 112 3345 23234 /myData/file1 101 2344 23201 /myData/file2 213 5689 46435 total
wc command with other Unix commands
wc command can be used in combination wit other commands using piping to get information.
Count records in CSV files
To count the number of records in files the wc can used with pipes. Find out the records in all csv files(There are 5 csv files). This can be achieved by piping the output of the cat command to wc.
$ cat *.csv | wc -l 2122 There are 2122 records across the 5 files.
Count the number files in a directory
To count the number of folders and files in a directory wc can be combined with the ls command. By passing the -1 options to ls it will list one file per line. This can be piped to wc to give a count.
$ ls -1 | wc -l 16
count number of times word appeared in a file
You can use grep command to count the number of times “word” appears in the file.
$ grep -o -i smart example.txt | wc -l Output: 3
Using grep -c alone will count the number of lines that contain the matching word instead of the number of total matches. To know about about grep refer here. The -o option is what tells grep to output each match in a unique line and then wc -l tells wc to count the number of lines. This is how the total number of matching words is deduced.