Convert case directly within the line of Linux

osc_zcxehg9f 2020-11-08 08:59:59
convert case directly line linux

Reading guide When editing text, case is often the place to pay attention to , Case conversion is a tedious and tedious job , Fortunately ,Linux  There are a lot of things that can make this job easy command . Next, let's look at some of the cases that are converted command .

 stay Linux Convert case directly within the line in Linux Convert case directly within the line

tr command

tr (translate) It can be used on the command line or Script One of the simplest case conversion commands on . For example, if you want a string to be all uppercase , You can do this with the command shown below :

$ echo hello alvin | tr [:lower:] [:upper:]

The following is how the command is applied to Script Examples , write file depts The content of the plenary session is in capital form :

$ echo "Enter department name: " | tr [:lower:] [:upper:] >> depts

The order of the above commands is changed to [:upper:] [:lower:] It's going to get the opposite result , All letters entered will be lowercase :

$ echo "Enter department name: " | tr [:upper:] [:lower:] >> depts

You can use it. A-Z a-z Instead of [:upper:] [:lower:] To achieve the same effect :

$ echo "Enter department name: " | tr a-z A-Z >> depts

awk command

awk Order to use toupper and tolower These two options complete the case conversion . The case conversion of the script described above can be done with this command in the following way :

$ echo "Enter department name: " | awk '{print toupper($0)}' >> depts

The above is converted to capital letters , Here's how to convert to lower case letters :

$ echo "Enter department name: " | awk '{print tolower($0)}' >> depts

sed command

sed (stream editor) The command can also do the case conversion well , The following command can also achieve the effect of the previous two commands :

$ echo "Enter department name: " | sed 's/[a-z]/\U&/g' >> depts

To complete the reverse conversion , Just put the U Switch to L 、[a-z] Switch to [A-Z] that will do :

$ echo "Enter department name: " | sed 's/[A-Z]/\L&/g' >> depts

Change the case of the text in the file
awk and sed Command can complete the case conversion of the entire document content , So if you need to convert the entire document to lowercase , You can use the following command to output the contents of a file in lowercase to the screen :

$ awk '{print tolower($0)}' depts

The result is as follows :

enter department name:

Note that this result only converts what is printed on the screen to lowercase , There is no change in capital letters in the document itself , Use cat depts Command to see . If you want to really change the case of the document content , You can do this with the following command :

$ awk '{print tolower($0)}' depts > depts-
$ mv depts- depts

sed Commands can be done and awk Same function , It's just a little different in usage , Its usage is as follows :

$ sed 's/[A-Z]/\L&/g' depts

Just capitalize the first letter

Capitalize only the first letter of each word in a string , This can be done with the following command :

$ echo design \& engineering| sed -e "s/\b\(.\)/\u\1/g"
Design & Engineering

The above command can only capitalize the first letter and keep the rest of the letters unchanged .

Make sure that only the initials are capitalized

When you need to do this with a lot of text , For example, to display the names of a large number of people in the correct format , What needs to be done will be a little harder . Here are two ways to do this :

use sed Command complete

To make sure the results are correct , It needs to be more complicated sed Command format :

$ echo design \& ENGINEERING | sed 's/\b\([[:alpha:]]\)\([[:alpha:]]*\)\b/\u\1\L\2/g'
Design & Engineering

use python Code completion

If your Linux Installed on python , You can use the following command to complete the capitalization of the text ,python The code is better than above sed The regular form of a command is much easier to understand :

$ echo -n "design & engineering" | python3 -c "import sys; print("
Design & Engineering

Linux There are many commands for case conversion , Which one works better depends on whether you're dealing with a string of characters or an entire file . I hope the various commands in this article can help you , If you have any questions about these orders , Feel free to leave a comment !Linux It's time to learn


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