Summary of several methods for shell to get string length

Time:2020-1-11

Preface

In our daily work, string operation is very common in shell scripts, and there are many ways to achieve it. Here are a few possible ways to find strings. Let’s have a look at the detailed introduction.

The method is as follows:

[method 1]: use ${ා STR} to get the length of the string

[method 2]: using the length method of awk

Remarks:

1) it is better to use {} to place variables

2) it can also be usedlength($0)To count the length of each line in the file

[method 3]: use NF term of awk to get string length

Remarks:-F is the separator, NF is the number of fields, that is, the length of a single line string

[method 4]: use the – L parameter of WC to get the length of string

Remarks:-L parameter

1) for multi line files, it means the length of the longest line to be printed! 82, indicating that the maximum line length of the / etc / passwd file is 82

2) For a single line string, the length of the current line string!

[method 5]: using the – L parameter of WC and echo – n parameter

Remarks:

1) – C parameter: count the number of characters

2) – n parameter: remove the “\ n” line break. If it is not removed, the default is line break. The number of characters is 7

[method 6]: using the length method of expr

[method 7]: using expr’s $STR: “. *” technique

Remarks:. * stands for any character, that is, any character is used to match the string, and the result is to match to 6 characters, that is, the length of the string is 6

summary

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