Replace slash in Bash
RegexLinuxBashTrSlashRegex Problem Overview
Let's suppose I have this variable:
DATE="04\Jun\2014:15:54:26"
Therein I need to replace \ with \/ in order to get the string:
"04\/Jun\/2014:15:54:26"
I tried tr as follows:
echo "04\Jun\2014:15:54:26" | tr '\' '\\/'
But this results in: "04\Jun\2014:15:54:26".
It does not satisfy me. Can anyone help?
Regex Solutions
Solution 1 - Regex
No need to use an echo + a pipe + sed.
A simple substitution variable is enough and faster:
echo ${DATE//\//\\/}
#> 04\/Jun\/2014:15:54:26
Solution 2 - Regex
Use sed for substitutions:
sed 's#/#\\/#g' < filename.txt > newfilename.txt
You usually use "/" instead of the "#", but as long as it is there, it doesn't matter.
I am writing this on a windows PC so I hope it is right, you may have to escape the slashes with another slash.
sed explained, the -e lets you edit the file in place. You can use -i to create a backup automatically.
sed -e s/STRING_TO_REPLACE/STRING_TO_REPLACE_IT/g index.html
Solution 3 - Regex
You can also escape the slashes, with a slightly less readable solution than with hashes:
echo "04/Jun/2014:15:54:26" | sed 's/\//\\\//g'
Solution 4 - Regex
here you go:
kent$ echo "04/Jun/2014:15:54:26"|sed 's#/#\\/#g'
04\/Jun\/2014:15:54:26
your tr line was not correct, you may mis-understand what tr does, tr 'abc' 'xyz' will change a->x, b->y, c->z,not changing whole abc->xyz..
Solution 5 - Regex
This has not been said in other answers so I thought I'd add some clarifications:
tr uses two sets of characters for replacement, and the characters from the first set are replaced with those from the second set in a one-to-one correspondance. The manpage states that
> SET2 is extended to length of SET1 by repeating its last character as necessary. Excess characters of SET2 are ignored.
Example:
echo abca | tr ab de # produces decd
echo abca | tr a de # produces dbcd, 'e' is ignored
echo abca | tr ab d # produces ddcd, 'd' is interpreted as a replacement for 'b' too
When using sed for substitutions, you can use another character than '/' for the delimiter, which will make your expression clearer (I like to use ':', @n34_panda proposed '#' in their answer). Don't forget to use the /g modifier to replace all occurences: sed 's:/:\\/:g' with quotes or sed s:/:\\\\/:g without (backslashes have to be escaped twice).
Finally your shortest solution will probably be @Luc-Olivier's answer, involving substitution, in the following form (don't forget to escape forward slashes too when part of the expected pattern):
echo ${variable/expected/replacement} # will replace one occurrence
echo ${variable//expected/replacement} # will replace all occurrences