Exploring echo and Colorful echo
echo command
echo command is used to places the text in the terminal or console
1) Create a file using the echo command.
1 | $ echo "The Linux Tips" > myfile.txt |
2) Append the text in the existing file
1 2 3 4 5 6 7 8 | $ cat myfile.txt The Linux Tips $ echo "The Linux Tips - Second Line" >> myfile.txt $ cat myfile.txt The Linux Tips The Linux Tips - Second Line |
3) echo and its arguments
-n -> It will not output the trailing newline
1 2 | $ echo -n "The Linux Tips" The Linux Tips$ |
Normal one ( trailing newline )
1 2 3 | $ echo "The Linux Tips" The Linux Tips $ |
-e -> It will enable the interpretation of backslash escapes
1 2 3 4 | #In the below example, i used \n (new line), but without using -e it prints the \n $ echo "The Linux \n Tips " The Linux \n Tips |
1 2 3 | $ echo -e "The Linux \n Tips" The Linux Tips |
1 2 3 4 5 6 | #In the below example, i used \t (tab), but without using -e it prints the \t $ echo "The Linux\tTips" The Linux\tTips $ echo -e "The Linux\tTips" The Linux Tips |
With effective to -e option, we can use the below options
1 2 3 | #print the \ (back slash) $ echo -e "\\" |
\
1 2 3 4 | # \b is for backspace. In the below example, you can see the d character is removed $ echo -e "abcd\bef" abcef |
1 2 3 4 | # \c is used produce no further output. In the below example, ef is not printed $ echo -e "abcd\cef" abcd$ |
1 2 3 4 | # \e is used for escape $ echo -e "abcd\eef" abcdef |
1 2 3 4 5 | # \f is for form feed. $ echo -e "abcd\fef" abcd ef |
1 2 3 4 | # \r is for carriage return $ echo -e "abcd\ref" efcd |
1 2 3 4 | # \t is for horizontal tab $ echo -e "abcd\tef" abcd ef |
1 2 3 4 5 | # \v is for vertical tab $ echo -e "abcd\vef" abcd ef |
-E -> disable interpretation of backslash escapes (default)
1 2 3 4 5 6 | $ echo -E "The Linux \n Tips" The Linux \n Tips $ echo -e "The Linux \n Tips" The Linux Tips |
echo and its colors
The below program is using ANSI escape code SGR sequences. ( For more about the SGR sequence, search “Ansi escape code + wiki” in google )
Type the below program and save it as colors.sh
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | $ cat colors.sh #!/bin/sh FGRED=`echo "\033[31m"` FGCYAN=`echo "\033[36m"` BGRED=`echo "\033[41m"` FGBLUE=`echo "\033[35m"` BGGREEN=`echo "\033[42m"` NORMAL=`echo "\033[m"` echo "${FGBLUE} Text in blue ${NORMAL}" echo "Text normal" echo "${BGRED} Background in red" echo "${BGGREEN} Background in Green and back to Normal ${NORMAL}" |
Assign the execute permission and execute the script. code tag didn’t show the colors 🙁 in this page
1 2 3 4 5 | $ ./colors.sh Text in blue Text normal Background in red Background in Green and back to Normal |
After executing the script, you can see some colorful text and background colors
Change the numbers after the “[” ( opening square bracket ) and see the difference
For more information about colors, see here
Try with other numeric combinations and see different colors 🙂
bye
kamaraj
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