tr
tr linux command cheatsheet by Thamizhiniyan C S
Introduction
Translate command(tr) can help you in number of ways, ranging from changing character cases in a string to replacing characters in a string.
Syntax
tr [flags] [source]/[find]/[select] [destination]/[replace]/[change]
Important Flags
-d
To delete a given set of characters
-t
To concat source set with destination set(destination set comes first; t stands for truncate)
-s
To replace the source set with the destination set(s stands for squeeze)
-c
This is the REVERSE card in this game, for eg. If you specify -c with -d to delete a set of characters then it will delete the rest of the characters leaving the source set which we specified (c stands for complement; as in doing reverse of something)
[:alnum:]
all letters and digits
[:alpha:]
all letters
[:blank:]
all horizontal whitespace
[:cntrl:]
all control characters
[:digit:]
all digits
[:graph:]
all printable characters, not including space
[:lower:]
all lower case letters
[:print:]
all printable characters, including space
[:punct:]
all punctuation characters
[:space:]
all horizontal or vertical whitespace
[:upper:]
all upper case letters
[:xdigit:]
all hexadecimal digits
[=CHAR=]
all characters which are equivalent to CHAR
Examples
cat file.txt | tr -s '[a-z]' '[A-Z]'
Convert every alphabetic character to upper case
cat file.txt | tr -s '[:lower:]' '[:upper:]'
Convert every alphabetic character to upper case
cat creds.txt | tr -d '[a-zA-Z: ]'
To view creds of a user which are in digits
tr '()' '[]'
To replace all parentheses ( ) with box brackets [ ]
tr -d a-z
To delete all the lowercase characters a-z
tr -s ' '
To replace all sequences of multiple spaces with just one space
tr [:space:] "\t"
Translates all the white-space characters to tabs
tr -d [:digit:]
To remove all the digits from the string
tr -cd [:digit:]
To remove all characters except digits ( complement )
tr -cs 'i' '0'
Replaces all characters except i with 0 and then squeezes the repeated 0 characters
tr -cs '[:alnum:]' '\n'
To put each word in a new line
tr -s '\n'
To delete the blank lines simply squeeze the repetitive newline characters
echo $PATH | tr ':' '\n'
To print each directory on a separate line from the PATH environment variable
cat .leftShift3 | tr "d-za-cD-ZA-C" "a-zA-Z"
Decrypt the Caesar cipher in the .leftshift3 file
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