Question Collection of Linux noodles

1, give you a RPM package, query whether installed, installed how to delete

Rpm-qa rsync to see if the Rsync pack is installed

Rpm-e rsync Offload rsync pack--nodeps ignore dependencies

2. View disk space

Df-h

3, 443 port is what service

Cat/etc/service

Https

4, Some files, how to change the file extension. txt to. html

Method 1:

Rename. txt. html *.txt

Method 2:

Find. -type f-name "*.txt"-print0 | xargs-0 rename. txt. html {}

Using the-print0 and Xargs-0 options of Find, you can resolve a problem that contains spaces in the file name.

Method 3:

for file in *.txt; Do MV $file ${file%.txt}.html; Done

5. Query the line number of empty line inside file

Grep-n ^$ 123.sh

Grep-n ^$ 123.sh |awk-f ': ' {print $} '

Sed-n '/^$/= ' 123.sh

awk ' $ ~/^$/{print NR} ' 123.sh

6. Query File1 the line ending with ABC

grep-ntmp$ 123.sh Excellent

sed-n '/tmp$/= ' 123.sh

7. Print out the first to third line of file1 files

Head-3 123.sh

Sed-n ' 1,3p ' 123.sh

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