Linux shell string interception, replacement, deletion, and trim code examples

Updated: Mar 01, 2024 14:54:24 by aabond

In Shell programming, intercept, replace, delete string is a very common operation, this article mainly introduces you about Linux shell string intercept, replace, delete and trim related information, the article through the code is very detailed, the need of friends can refer to the next

catalogue

String interception

Cut the string after the first // from left to right

word=abcd-//master-01://httpab echo ${word#*//} # Output :master-01://httpab

Cut the string after the last // from left to right

Word = abcd - / / master - 01: / / httpab echo ${word# # * / /} # output: httpab

Cut the string after the first // from right to left

Word = abcd - / / master - 01: / / httpab echo ${word % / / *} # output: abcd - / / master - 01:

Cut the string after the last // from right to left

Word = abcd - / / master - 01: / / httpab echo ${word % % / / *} # output: abcd -

Intercept 3 characters after position 0

word=abcd-//master-01://httpab echo ${word:0:3} # Output :abc

Cut from position 1 to the end

word=abcd-//master-01://httpab echo ${word:1} # Output :bcd-//master-01://httpab

Cut from position -1 to the end, that's the last one

Word = abcd - / / master - 01: / / httpab echo ${word: (1)} # output: b

String substitution

From left to right, match the first one and replace // with cd

word=abcd-//master-01://httpab echo ${word/\/\//cd} # Output: abcd-CDmaster-01 ://httpab

Replace all matching // with cd

word=abcd-//master-01://httpab echo ${word//\/\//cd} # Output: abcd-CDmaster-01 :cdhttpab

Prefix matching: matches only characters starting from position 0

word=abcd-//master-01://httpab echo ${word/#ab/cd} # - Not a prefix, echo ${word/#-/cd} # Output :abcd-cdmaster-01://httpab # Output :abcd-//master-01://httpab

Suffix matching. Only the end character is matched

Word = abcd - / / master - 01: / / httpab echo ${word/HTTP * / x, y} % # output: abcd - / / master - 01: / / xy echo ${word/ab/x, y} % # Output :abcd-//master-01://httpxy echo ${word/%ab*/xy} # * appears and matches # from the start output :xy

String deletion

The effect of deleting characters can be achieved by using character interception, substitution and concatenation

Delete the first 3 characters

Word = abcd - / / master - 01: / / httpab echo ${word# * ${word: 3-0}} # output: d - / / master - 01: / / httpab

Delete after 3 characters

Word = abcd - / / master - 01: / / httpab echo ${word % * ${word: (3)}} # output: abcd - / / master - 01: / / HTTP

Delete the first ab

word=abcd-//master-01://httpab echo ${word/ab/} # Output :cd-//master-01://httpab

Delete all ab

Word = abcd - / / master - 01: / / httpab echo ${word / / ab /} # output: CD / / master - 01: / / HTTP

Delete the last ab

Word = abcd - / / master - 01: / / httpabcd echo ${word % ab *} ${word# # * ab} # output: abcd - / / master - 01: / / HTTPCD

String trim

trim can be implemented with xargs

word=" hello wolrd "word= 'echo $word | xargs' echo $word # Output :hello wolrd

Reference blog: / / www.jb51.net/jiaoben/316765sh8.htm

Sum up

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