Shell--cat,find,xargs,tr,sort,grep

A Cat

1.cat file1 file2 file3 ...

2. Use a pipe to read from the standard input:

echo "Hadoop hive!" | Cat–file.txt

3. Compress Blank Lines

(1) Compress multiple continuous whitespace behaviors single

Cat-s file

(2) Remove blank lines

Cat File.txt | Tr-s ' \ n '

4.cat-t file; Show tab is ^

5.cat-n file; Show line Numbers

Two Recording and playback terminal answering

Script-t 2> Timing.log-aoutput.sessin

...

Exit

Scriptreplay Timing.log output.session

Three Find

1. Traverse down the file hierarchy to match the eligible files.

2. Find. –print;

-print is a delimiter using ' \ n ' as a delimiter,-print0 indicates using ' \ s ' as the delimiter.

-NAME specifies a string that matches the file name,-iname ignores the case

Find/usr/local-name "*.txt"-print

Find.  !  -name "*.txt"-print; 。 Contains a negative meaning, not the txt end of the file name

Find. \ (-name "*.txt" –o–name "*.pdf" \) –print

Find/usr/local-path "*.txt"-print

3. Search based on directory depth and file type

Find. –maxdepth 1–type F-print

Find. –mindepth 2-type F-print

-type can filter the search file

Normal file	F
Symbolic Links	L
Directory	D
Character device	C
Block devices	B
Sockets	S
Fifo	P

4. File time-based search

Access time:-atime,-amin

Modified:-mtime,-mmin

Change time:-ctime,-cmin

Find. –type f–atime +7–print; Print all files that have been accessed for longer than 7 days

-newer: Find all files that are updated (longer modified) than the reference file

Find. –type F-newer File.txt-print

5. File-size-based search

Find. –type f-size +2k

6. Delete matching files

Find. –type-f–name "*txt" –delete

7. File-based permissions and ownership matching

Find. –type F-perm 666–print

8. Find files owned by a specific user

Find. –type F-user Cw-print

9.find combined with –exec{}

Find. –type f–name "*.txt" –exec cp {}/usr/local \;

Find. –type f–name "*.pdf" –exec printf "text file:%s\n" {} \;

Find. Type F–name "*.cpp" –exec Cat {} \;>all.out

Four Xargs

1.xargs specializes in converting standard input data to command line parameters

2. Convert multi-line input to single-line output

Cat File.txt | Xargs

3. Convert single-line input to multi-line output

Cat File.txt | Xargs–n 4

4. Splitting parameters with delimiters

echo "Splitxshellxhadoop" | Xargs–d X-n 2

Cat file.txt |xargs-n 2./demo.sh;//The data in file is passed to demo.sh as a parameter every 2 times.

Five TR Conversion command

1.tr can only be accepted by stdin, not by command-line arguments

2. Convert the input character from uppercase to lowercase

echo "HELLO" | Tr ' A-Z ' A-Z

echo 1234 | Tr ' 0-9 ' 9876543210 '

Cat File.txt | Tr ' \ n '

3. Specify the character set to delete

Cat File.txt | Tr–d ' 0-9 '

4. Delete complement-C

echo "Hello 1 hive3 hadoop2" | Tr–d–c ' 0-9 \ n ';

Delete all characters except the collection

5.tr Compression character-S

echo "Gun isn't right?" | Tr–s "; Compress spaces

Add a number from a file

Cat Sum.txt

1

2

3

4

Cat Sum.txt | echo$[$ (tr ' \ n ' + ') 0], the tail is more than a + number all plus 0.

Six Sort

1.sort file1.txt file2.txt > Sort.txt

2.sort-n file.txt; Sort by number

3.sort-r file.txt; Reverse order

4.sort-m file.txt; Sort by month

5.sort-m Sort1.txt sort2.txt; merging merged files, no longer sorted

6.sort-k 2 file.txt; sort the second column

7.SORT-NRK 1 file.txt; Sort the first column in reverse order by number

Seven. grep

grep is used to search for a specified string in a file

1. Search for files with string bin under directory

Grep bin *

2. explicitly require search subdirectories; grep-r

3. Ignore subdirectories: grep-d Skip

4. Search by case insensitive: Grep-i pattern files

5. List only matching filenames: Grep-l pattern files

6. List filenames that do not match: Grep-l pattern files

7. Match only the entire word, not part of the string: Grep-w pattern files

8. Match the previous afternoon showing [number] line: Grep–c number pattern files

9. Show rows Matching pattern1 or pattern2: grep pattern1 | PATTERN2 files

10. Show rows that match both: grep pattern1 Files | grep pattern2

\< and \> each mark the beginning and end of a word.

12. ' ^ ' means match string at the beginning of the line, ' $ ' refers to the string at the end of the line