mapfile -tn 0 lines < "$1" printf '%s\n' "${#lines[@]}" } 1. 2. 3. 4. 5. 示例函数(bash 3): 此方法使用的内存少于mapfile方法,并在bash3中工作,但对于较大的文件,它的速度较慢。 lines_loop() { # Usage: lines_loop "file" count=0 while IFS= read -r _; do ((count++))...
mapfile -tn 0 lines < "$1" printf '%s\n' "${#lines[@]}" } 示例函数(bash 3): 此方法使用的内存少于mapfile方法,并在bash3中工作,但对于较大的文件,它的速度较慢。 lines_loop() { # Usage: lines_loop "file" count=0 while IFS= read -r _; do ((count++)) done < "$1" printf...
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Theread -rcommand reads the file and stores the strings to thelinevariable. Next, theecho $linedisplays the lines to the standard output. Lastly, thefilenamevariable is given as an input to the while loop. In the following example, I am giving thescript.shas the file name to read. Ba...
代码如下:data = file.read(-1)读取文件内容后,我们可以使用 split() 方法来将文件内容分割成行。...代码如下:lines = data.split('\n')现在,我们就可以使用 lines 列表来访问文件中的每一行数据了。...例如,要访问第一行数据,我们可以使用以下代码:line1 = lines[0]要访问第二行数...
# This may cause problem, check the value of 'i' at the end of the loop echo"###" cat$FILE |whilereadline;do echo"Line # $i: $line" ((i++)) done echo"Total number of lines in file: $i" # The worst way to read file. echo"##...
v ## The loop calls getopts until there are no more options on the command line ## Each option is stored in $opt, any option arguments are stored in OPTARG while getopts $optstring opt do case $opt in f) filename=$OPTARG ;; ## $OPTARG contains the argument to the option v) ...
# This may cause problem, check the value of'i'at theendof the loop echo"###" cat$FILE|whileread line;do echo"Line # $i: $line" ((i++)) done echo"Total number of lines in file: $i" # The worst way to read file. echo"##...
In this example, the ‘for’ loop iterates over all .txt files in the current directory, echoing a statement for each file. These advanced uses of the ‘foreach’ loop in Bash open up a world of possibilities for automating tasks and processing data. As you explore these techniques, remem...
while read -r line; do printf '%s\n' "$line" done < "file"Loop over files and directoriesDon’t use ls.# Greedy example. for file in *; do printf '%s\n' "$file" done # PNG files in dir. for file in ~/Pictures/*.png; do printf '%s\n' "$file" done # Iterate over ...