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How to add prefix string to beginning of each line?
If you need to prepend a text at the beginning of each line that has a certain string, try following. In the following example, I am adding # at the beginning of each line that has the word “rock” in it. Simple solution using a for loop on the command line with bash:
Is it possible to insert prefix to all output of Bash?
Bash itself may also output some text. But if a few scripts are running at the same time, it is hard to identify where does an error come from. So is it possible to insert a prefix to all output of the script?
How to replace every line in shell with myprefix?
Now I wonder if there is another way to do that in shell. This replaces every line beginning ^ with myprefix_. Note that ^ is not lost, so this allows to add content to the beginning of each line. It seems like the bash solution is much slower.. The -d option is used to allow input line with trailing blanks (related to -L spec).
Where does the text come from when Bash is running?
Closed 3 years ago. When a script runs, commands in it may output some text to stdout/stderr. Bash itself may also output some text. But if a few scripts are running at the same time, it is hard to identify where does an error come from.
How to use prefix and suffix in Perl?
But note, this suffers from problems with filenames with line feeds, and all the assorted problems of parsing ls which is generally a bad idea. Note – perl grep can take a pattern – like the grep command, but you can also do things like apply file tests.
Is it possible to insert prefix to all output of a script?
But if a few scripts are running at the same time, it is hard to identify where does an error come from. So is it possible to insert a prefix to all output of the script? Something like: #!/bin/bash prefix ‘PREFIX’ &2 echo “wrong!” >&2 $ ./script.sh PREFIXwrong!
How to prefix and suffix a string in grep?
When grep outputs, it returns (usually) many lines. I would like to prefix and suffix a string to each of these output lines. I would also like to note that I’m piping ls into grep, like: But note, this suffers from problems with filenames with line feeds, and all the assorted problems of parsing ls which is generally a bad idea.
How to get the same output as a plain LS?
This handles filenames with whitespace, including newlines. compgen -G “*” should provide the same output as a plain ls (but note that ls * is a different thing entirely). You’ll still need grep, and this may or may not solve the problem, but it’s worth a mention.
How to check if a string contains a substring in Bash?
#!/bin/bash STR=’GNU/Linux is an operating system’ SUB=’Linux’ case $STR in *”$SUB”*) echo -n “It’s there.” ;; esac Another option to determine whether a specified substring occurs within a string is to use the regex operator =~. When this operator is used, the right string is considered as a regular expression.
How to create two different strings in Bash?
If you are in a bash session, you could do a: with < creating anonymous named pipes — managed by bash — so they are created and destroyed automatically, unlike temporary files. So if you manage to isolate your two different string as part of a command (grep, awk, sed.), you can do – for instance – something like:
Is the syntax in Bash the same as in SH?
Given how old, arcane and crufty sh is (and Bash is not the cure: It’s more complicated, less consistent and less portable), I’d like to point out a very nice functional aspect: While some syntax elements like case are built-in, the resulting constructs are no different than any other job. They can be composed in the same way: